Misplaced Pages

Major League Baseball

Major League Baseball (MLB) is a professional baseball league and the highest level of organized baseball in the United States and Canada. One of the "Big Four" major professional sports leagues in the United States and Canada, MLB comprises 30 teams, divided equally between the National League (NL) and the American League (AL), with 29 in the United States and 1 in Canada. Formed in 1876 and 1901, respectively, the NL and AL cemented their cooperation with the National Agreement in 1903, making MLB the oldest major professional sports league in the world. They remained legally separate entities until 2000, when they merged into a single organization led by the commissioner of baseball. MLB is headquartered in Midtown Manhattan.

Baseball's first all-professional team, the Cincinnati Red Stockings, was founded in 1869. The first few decades of professional baseball saw rivalries between leagues, and players often jumped from one team or league to another. These practices were essentially ended by the National Agreement of 1903, in which AL and NL agreed to respect each other's player contracts, including the contentious reserve clause.

The period before 1920 was the dead-ball era, when home runs were rarely hit. Professional baseball was rocked by the Black Sox Scandal, a conspiracy to fix the 1919 World Series. Baseball survived the scandal, albeit with major changes in its governance as the relatively weak National Commission was replaced with a powerful commissioner of baseball with near-unlimited authority over the sport.

MLB rose in popularity in the decade following the Black Sox Scandal, and unlike major leagues in other sports it endured the Great Depression and World War II without any of its teams folding. Shortly after the war, Jackie Robinson broke baseball's color barrier.

Some teams moved to different cities in the 1950s and 1960s. The AL and NL added eight clubs in the 1960s: two in 1961, two in 1962, and four in 1969. Player discontent with established labor practices, especially the reserve clause, led to the organization of the Major League Baseball Players Association to collectively bargain with the owners, which in turn led to the introduction of free agency in baseball.

Modern stadiums with artificial turf surfaces began to change the game in the 1970s and 1980s. Home runs dominated the game during the 1990s. In the mid-2000s, media reports disclosed the use of anabolic steroids among MLB players; a 2006–07 investigation produced the Mitchell Report, which found that many players had used steroids and other performance-enhancing substances, including at least one player from each team.

Each team plays 162 games per season, with Opening Day traditionally held during the first week of April. Six teams in each league then advance to a four-round postseason tournament in October, culminating in the World Series, a best-of-seven championship series between the two league champions first played in 1903. The New York Yankees have the most championships with 27. The reigning champions are the Los Angeles Dodgers, who defeated the New York Yankees in the 2024 World Series.

MLB is the third-wealthiest professional sports league by revenue in the world after the National Football League (NFL) and the National Basketball Association (NBA). Baseball games are broadcast on television, radio, and the internet throughout North America and in several other countries. MLB has the highest total season attendance of any sports league in the world; in 2023, it drew more than 70.75 million spectators.

MLB also oversees Minor League Baseball, which comprises lower-tier teams affiliated with the major league clubs, and the MLB Draft League, a hybrid amateur-professional showcase league. MLB and the World Baseball Softball Confederation jointly manage the international World Baseball Classic tournament.

In the 1860s, aided by soldiers playing the game in camp during the Civil War, "New York"-style baseball expanded into a national game and spawned baseball's first governing body, the National Association of Base Ball Players (NABBP). The NABBP existed as an amateur league for 12 years. By 1867, more than 400 clubs were members. Most of the strongest clubs remained those based in the Northeastern United States. For professional baseball's founding year, MLB uses the year 1869—when the first professional team, the Cincinnati Red Stockings, was established.

A schism developed between professional and amateur ballplayers after the founding of the Cincinnati club. The NABBP split into an amateur organization and a professional organization. The National Association of Professional Base Ball Players, often known as the National Association (NA), was formed in 1871. Its amateur counterpart disappeared after only a few years. The modern Chicago Cubs and Atlanta Braves franchises trace their histories back to the National Association of Professional Base Ball Players in the 1870s.

In 1876, the National League of Professional Base Ball Clubs (later known as the National League or NL) was established after the NA proved ineffective. The league placed its emphasis on clubs rather than on players. Clubs could now enforce player contracts, preventing players from jumping to higher-paying clubs. Clubs were required to play the full schedule of games instead of forfeiting scheduled games when the club was no longer in the running for the league championship, which happened frequently under the NA. A concerted effort was made to curb gambling on games, which was leaving the validity of results in doubt. The first game in the NL—on Saturday, April 22, 1876 (at Jefferson Street Grounds in Philadelphia)—is often pointed to as the beginning of MLB.

The early years of the NL were tumultuous, with threats from rival leagues and a rebellion by players against the hated "reserve clause", which restricted the free movement of players between clubs. Teams came and went; 1882 was the first season where the league's membership was the same as the preceding season's, and only four franchises survived to see 1900. Competitor leagues formed regularly and also disbanded regularly. The most successful was the American Association (1882–1891), sometimes called the "beer and whiskey league" for its tolerance of the sale of alcoholic beverages to spectators. For several years, the NL and American Association champions met in a postseason championship series—the first attempt at a World Series. The two leagues merged in 1892 as a single 12-team NL, but the NL dropped four teams after the 1899 season. This led to the formation of the American League in 1901 under AL president Ban Johnson, and the resulting bidding war for players led to widespread contract-breaking and legal disputes.

The war between the AL and NL caused shock waves throughout the baseball world. At a meeting at the Leland Hotel in Chicago in 1901, the other baseball leagues negotiated a plan to maintain their independence. A new National Association was formed to oversee these minor leagues.

After 1902, the NL, AL, and NA signed a new National Agreement which tied independent contracts to the reserve-clause contracts. The agreement also set up a formal classification system for minor leagues, the forerunner of today's system that was refined by Branch Rickey.

Several other early defunct baseball leagues are considered major leagues, and their statistics and records are included with those of the two modern major leagues. In 1969, the Special Baseball Records Committee of Major League Baseball officially recognized six major leagues: the National League, American League, American Association, Union Association (1884), Players' League (1890), and Federal League (1914–1915). The status of the National Association as a major league has been a point of dispute among baseball researchers; while its statistics are not recognized by Major League Baseball, its statistics are included with those of other major leagues by some baseball reference websites, such as Retrosheet. Some researchers, including Nate Silver, dispute the major-league status of the Union Association by pointing out that franchises came and went and that the St. Louis club was deliberately "stacked"; the St. Louis club was owned by the league's president and it was the only club that was close to major-league caliber.

In December 2020, Major League Baseball announced its recognition of seven leagues within Negro league baseball as major leagues: the first and second Negro National Leagues (1920–1931 and 1933–1948), the Eastern Colored League (1923–1928), the American Negro League (1929), the East–West League (1932), the Negro Southern League (1932), and the Negro American League (1937–1948). In 2021, baseball reference website Baseball-Reference.com began to include statistics from those seven leagues into their major-league statistics. In May 2024, Major League Baseball announced that it was "absorbing the available Negro Leagues numbers into the official historical record."

The period between 1900 and 1919 is commonly referred to as the "dead-ball era". Games of this era tended to be low-scoring and were often dominated by pitchers, such as Walter Johnson, Cy Young, Christy Mathewson, Mordecai Brown, and Grover Cleveland Alexander. The term also accurately describes the condition of the baseball itself. The baseball used American rather than the modern Australian wool yarn and was not wound as tightly, affecting the distance that it would travel. More significantly, balls were kept in play until they were mangled, soft and sometimes lopsided. During this era, a baseball cost three dollars, equal to $52.72 today (in inflation-adjusted USD), and owners were reluctant to purchase new balls. Fans were expected to throw back fouls and (rare) home runs. Baseballs also became stained with tobacco juice, grass, and mud, and sometimes the juice of licorice, which some players would chew for the purpose of discoloring the ball.

Also, pitchers could manipulate the ball through the use of the spitball (In 1921, use of this pitch was restricted to a few pitchers with a grandfather clause). Additionally, many ballparks had large dimensions, such as the West Side Grounds of the Chicago Cubs, which was 560 feet (170 m) to the center field fence, and the Huntington Avenue Grounds of the Boston Red Sox, which was 635 feet (194 m) to the center field fence, thus home runs were rare, and "small ball" tactics such as singles, bunts, stolen bases, and the hit-and-run play dominated the strategies of the time. Hitting methods like the Baltimore chop were used to increase the number of infield singles. On a successful Baltimore chop, the batter hits the ball forcefully into the ground, causing it to bounce so high that the batter reaches first base before the ball can be fielded and thrown to the first baseman.

The adoption of the foul strike rule—in the NL in 1901, in the AL two years later—quickly sent baseball from a high-scoring game to one where scoring runs became a struggle. Before this rule, foul balls were not counted as strikes: a batter could foul off any number of pitches with no strikes counted against him; this gave an enormous advantage to the batter.

After the 1919 World Series between the Chicago White Sox and Cincinnati Reds, baseball was rocked by allegations of a game-fixing scheme known as the Black Sox Scandal. Eight players—"Shoeless" Joe Jackson, Eddie Cicotte, Claude "Lefty" Williams, George "Buck" Weaver, Arnold "Chick" Gandil, Fred McMullin, Charles "Swede" Risberg, and Oscar "Happy" Felsch—intentionally lost the World Series in exchange for a ring worth $100,000 ($1,712,780.35 in 2022 dollars). Despite being acquitted, all were permanently banned from Major League Baseball.

Baseball's popularity increased in the 1920s and 1930s. The 1920 season was notable for the death of Ray Chapman of the Cleveland Indians. Chapman, who was struck in the head by a pitch and died a few hours later, became the only MLB player to die of an on-field injury. Both leagues quickly began to require the use of new, white baseballs whenever a ball became scuffed or dirty, helping bring the "dead-ball" era to an end.

The following year, the New York Yankees made their first World Series appearance. By the end of the 1930s, the team had appeared in 11 World Series, winning eight of them. Yankees slugger Babe Ruth had set the single-season home run record in 1927, hitting 60 home runs; breaking his own record of 29 home runs.

Afflicted by the Great Depression, baseball's popularity had begun a downward turn in the early 1930s. By 1932, only two MLB teams turned a profit. Attendance had fallen, due at least in part to a 10% federal amusement tax added to baseball ticket prices. Baseball owners cut their rosters from 25 men to 23, and even the best players took pay cuts. Team executives were innovative in their attempts to survive, creating night games, broadcasting games live by radio, and rolling out promotions such as free admission for women. Throughout the Great Depression, no MLB teams moved or folded.

The onset of World War II created a shortage of professional baseball players, as more than 500 men left MLB teams to serve in the military. Many of them played on service baseball teams that entertained military personnel in the US or in the Pacific. MLB teams of this time largely consisted of young men, older players, and those with a military classification of 4F, indicating mental, physical, or moral unsuitability for service. Men like Pete Gray, a one-armed outfielder, got the chance to advance to the major leagues. However, MLB rosters did not include any black players through the end of the war. Black players, many of whom served in the war, were still restricted to playing Negro league baseball.

Wartime blackout restrictions, designed to keep outdoor lighting at low levels, caused another problem for baseball. These rules limited traveling and night games to the point that the 1942 season was nearly canceled. On January 14, 1942, MLB Commissioner Kenesaw Mountain Landis wrote to U.S. President Franklin D. Roosevelt, pleading for the continuation of baseball during the war. Roosevelt responded, "I honestly feel that it would be best for the country to keep baseball going. There will be fewer people unemployed and everybody will work longer hours and harder than ever before. And that means that they ought to have a chance for recreation and for taking their minds off their work even more than before."

With the approval of President Roosevelt, spring training began in 1942 with few repercussions. The war interrupted the careers of stars including Stan Musial, Bob Feller, Ted Williams, and Joe DiMaggio, but baseball clubs continued to field their teams.

Branch Rickey, president and general manager of the Brooklyn Dodgers, began making efforts to introduce a black baseball player to the previously all-white professional baseball leagues in the mid-1940s. He selected Jackie Robinson from a list of promising Negro league players. After obtaining a commitment from Robinson to "turn the other cheek" to any racial antagonism directed at him, Rickey agreed to sign him to a contract for $600 a month. In what was later referred to as "The Noble Experiment", Robinson was the first black baseball player in the International League since the 1880s, joining the Dodgers' farm club, the Montreal Royals, for the 1946 season.

The following year, the Dodgers called up Robinson to the major leagues. On April 15, 1947, Robinson made his major league debut at Ebbets Field before a crowd of 26,623 spectators, including more than 14,000 black patrons. Black baseball fans began flocking to see the Dodgers when they came to town, abandoning the Negro league teams that they had followed exclusively. Robinson's promotion met a generally positive, although mixed, reception among newspaper writers and white major league players. Manager Leo Durocher informed his team, "I don't care if he is yellow or black or has stripes like a fucking zebra. I'm his manager and I say he plays."

After a strike threat by some players, NL President Ford C. Frick and Baseball Commissioner Happy Chandler let it be known that any striking players would be suspended. Robinson received significant encouragement from several major-league players, including Dodgers teammate Pee Wee Reese who said, "You can hate a man for many reasons. Color is not one of them." That year, Robinson won the inaugural Major League Baseball Rookie of the Year Award (separate NL and AL Rookie of the Year honors were not awarded until 1949).

Less than three months later, Larry Doby became the first African-American to break the color barrier in the American League with the Cleveland Indians. The next year, a number of other black players entered the major leagues. Satchel Paige was signed by the Indians and the Dodgers added star catcher Roy Campanella and Don Newcombe, who was later the first winner of the Cy Young Award for his outstanding pitching.

MLB banned the signing of women to contracts in 1952, but that ban was lifted in 1992. There have been no female MLB players since then.

From 1903 to 1952, the major leagues consisted of two eight-team leagues whose 16 teams were located in ten cities, all in the northeastern and mid-western United States: New York City had three teams and Boston, Chicago, Philadelphia, and St. Louis each had two teams. St. Louis was the southernmost and westernmost city with a major league team. The longest possible road trip, from Boston to St. Louis, took about 24 hours by railroad. After a half-century of stability, starting in the 1950s, teams began to move out of cities with multiple teams into cities that had not had them before. From 1953 to 1955, three teams moved to new cities: the Boston Braves became the Milwaukee Braves, the St. Louis Browns became the Baltimore Orioles, and the Philadelphia Athletics became the Kansas City Athletics.

The 1958 Major League Baseball season began to turn Major League Baseball into a nationwide league. Walter O'Malley, owner of the Brooklyn Dodgers and "perhaps the most influential owner of baseball's early expansion era," moved his team to Los Angeles, marking the first major league franchise on the West Coast. O'Malley also helped persuade the rival New York Giants to move west to become the San Francisco Giants. Giants owner Horace Stoneham had been contemplating a move to Minnesota amid slumping attendance at the aging Polo Grounds ballpark when O'Malley invited him to meet San Francisco Mayor George Christopher in New York. After Stoneham was persuaded to move to California, Time magazine put O'Malley on its cover. MLB Commissioner Ford C. Frick had opposed the meeting, but the dual moves proved successful for both franchises—and for MLB. Had the Dodgers moved out west alone, the St. Louis Cardinals—1,600 mi (2,575 km) away —would have been the closest NL team. Instead, the joint move made West Coast road trips economical for visiting teams. The Dodgers set a single-game MLB attendance record in their first home appearance with 78,672 fans.

In 1961, the first Washington Senators franchise moved to Minneapolis–St. Paul to become the Minnesota Twins. Two new teams were added to the American League at the same time: the Los Angeles Angels (who soon moved from downtown L.A. to nearby Anaheim) and a new Washington Senators franchise. The NL added the Houston Astros and the New York Mets in 1962. The Astros (known as the "Colt .45s" during their first three seasons) became the first southern major league franchise since the Louisville Colonels folded in 1899 and the first franchise to be located along the Gulf Coast. The Mets established a reputation for futility by going 40–120 during their first season of play in the nation's media capital—and by playing only a little better in subsequent campaigns—but in their eighth season (1969) the Mets became the first of the 1960s expansion teams to play in the postseason, culminating in a World Series title over the heavily favored Baltimore Orioles.

In 1966, the major leagues moved to the "Deep South" when the Braves moved to Atlanta. In 1968, the Kansas City Athletics moved west to become the Oakland Athletics. In 1969, the American and National Leagues both added two expansion franchises. The American League added the Seattle Pilots (who became the Milwaukee Brewers after one disastrous season in Seattle) and the Kansas City Royals. The NL added the first Canadian franchise, the Montreal Expos, as well as the San Diego Padres.

In 1972, the second Washington Senators moved to the Dallas–Fort Worth metroplex to become the Texas Rangers. In 1977, baseball expanded again, adding a second Canadian team, the Toronto Blue Jays, as well as the Seattle Mariners. Subsequently, no new teams were added until the 1990s and no teams moved until 2005.

By the late 1960s, the balance between pitching and hitting had swung in favor of the pitchers. In 1968—later nicknamed "the year of the pitcher" —Boston Red Sox player Carl Yastrzemski won the American League batting title with an average of just .301, the lowest in the history of Major League Baseball. Detroit Tigers pitcher Denny McLain won 31 games, making him the only pitcher to win 30 games in a season since Dizzy Dean in 1934. St. Louis Cardinals starting pitcher Bob Gibson achieved an equally remarkable feat by allowing an ERA of just 1.12.

Following these pitching performances, in December 1968 the MLB Playing Rules Committee voted to reduce the strike zone from knees to shoulders to top of knees to armpits and lower the pitcher's mound from 15 to 10 inches, beginning in the 1969 season.

In 1973, the American League, which had been suffering from much lower attendance than the National League, sought to increase scoring even further by initiating the designated hitter (DH) rule.

Throughout the 1960s and 1970s, as baseball expanded, NFL football had been surging in popularity, making it economical for many of these cities to build multi-purpose stadiums instead of single-purpose baseball fields. Because of climate and economic issues, many of these facilities had playing surfaces made from artificial turf, as well as the oval designs characteristic of stadiums designed to house both baseball and football. This often resulted in baseball fields with relatively more foul territory than older stadiums. These characteristics changed the nature of professional baseball, putting a higher premium on speed and defense over home-run hitting power since the fields were often too big for teams to expect to hit many home runs and foul balls hit in the air could more easily be caught for outs.

Teams began to be built around pitching—particularly their bullpens—and speed on the basepaths. Artificial surfaces meant balls traveled quicker and bounced higher, so it became easier to hit ground balls "in the hole" between the corner and middle infielders. Starting pitchers were no longer expected to throw complete games; it was enough for a starter to pitch 6–7 innings and turn the game over to the team's closer, a position which grew in importance over these decades. As stolen bases increased, home run totals dropped. After Willie Mays hit 52 home runs in 1965, only one player (George Foster) reached that mark until the 1990s.

During the 1980s, baseball experienced a number of significant changes the game had not seen in years. Home runs were on the decline throughout the decade, with players hitting 40 home runs just 13 times and no one hitting more than 50 home runs in a season for the first time since the Dead-ball era (1900–1919).

The 1981 Major League Baseball strike from June 12 until July 31 forced the cancellation of 713 total games and resulted in a split-season format.

In 1985, Pete Rose broke Ty Cobb's all-time hits record with his 4,192nd hit, and in 1989 Rose received a lifetime ban from baseball as a result of betting on baseball games while manager of the Cincinnati Reds. Rose was the first person to receive a lifetime ban from baseball since 1943. 1985 also saw the Pittsburgh drug trials which involved players who were called to testify before a grand jury in Pittsburgh related to cocaine trafficking.

The 1994–95 Major League Baseball strike from August 12, 1994, to April 25, 1995, caused the cancellation of over 900 games and the forfeit of the entire 1994 postseason.

Routinely in the late 1990s and early 2000s, baseball players hit 40 or 50 home runs in a season, a feat that was considered rare even in the 1980s. It later became apparent that at least some of this power surge was a result of players using steroids and other performance-enhancing drugs.

In 1993, the National League added the Florida Marlins in Miami and the Colorado Rockies in Denver. In 1998, the Brewers switched leagues by joining the National League, and two new teams were added: the National League's Arizona Diamondbacks in Phoenix and the American League's Tampa Bay Devil Rays in Tampa Bay.

Mickey Mantle

Mickey Charles Mantle (October 20, 1931 – August 13, 1995), nicknamed "the Mick" and "the Commerce Comet", was an American professional baseball player who played his entire Major League Baseball (MLB) career (1951–1968) with the New York Yankees, primarily as a center fielder. Mantle is regarded by many as being one of the best players and sluggers of all time. He was an American League (AL) Most Valuable Player three times and was inducted into the Baseball Hall of Fame in 1974.

Born in Spavinaw, Oklahoma, Mantle was raised by his father to become a baseball player and was trained early on to become a switch hitter. Despite a career plagued with injuries, beginning with his knee injury in the 1951 World Series, he became one of the greatest offensive threats in baseball history, and was able to hit for both average and power. He is the only player to hit 150 home runs from both sides of the plate. Mantle hit 536 career home runs while batting .300 or more ten times; he is 16th all-time in home runs per at-bat and 17th in on-base percentage.

Mantle won the Triple Crown in 1956, when he led the major leagues in batting average (.353), home runs (52), and runs batted in (RBI) (130). He was an All-Star for 16 seasons, playing in 16 of the 20 All-Star Games that he was selected for. He also had a solid .984 fielding percentage when playing center field, winning a Gold Glove in that position. He appeared in 12 World Series, winning seven championships, and holds World Series records for the most home runs (18), RBIs (40), extra-base hits (26), runs (42), walks (43), and total bases (123), and he has the highest World Series on-base and slugging percentages.

After retirement, Mantle worked as sports commentator for NBC for a few years and had a brief stint as first base and hitting coach for the Yankees in the 1970 season. Despite being one of the best-paid athletes of his era, he was a poor businessman and suffered financial setbacks from business failures. His private life was plagued by tumult and tragedy. His marriage fell apart due to his alcoholism and infidelity, and three of his sons became alcoholics, two of them dying from it. Towards the end of his life, Mantle came to regret his hard lifestyle and the damage he had inflicted on his family. Before his final year, he was treated for alcoholism and became sober, afterwards warning others of the dangers of hard drinking. He died from liver cancer brought on by years of alcohol abuse in Dallas, Texas, aged 63.

Mantle was born on October 20, 1931, in Spavinaw, Oklahoma, the son of Lovell Thelma (née Richardson; previously Davis) (1904–1995) and Elvin Charles "Mutt" Mantle (1912–1952). He was of at least partial English ancestry; his great-grandfather George Mantle left Brierley Hill, a small town in England's Black Country, and immigrated to the United States in 1848.

Mantle had two older half-siblings, Ted and Anna Bae Davis, from his mother's first marriage, and four younger full siblings: twin brothers Ray and Roy, brother Larry, and sister Barbara. When he was four years old, Mantle's family moved to the nearby town of Commerce, Oklahoma, where his father worked in lead and zinc mines.

A semi-pro player himself, Mutt Mantle decided that his eldest son would be a baseball player before Mantle was even born. He named his eldest son after Hall of Fame catcher Mickey Cochrane and, very early on, began training Mickey to become a switch-hitter: Mantle later recalled batting left-handed against his father, who pitched to him right-handed, and batting right-handed against his grandfather, Charles Mantle, who pitched to him left-handed.

In addition to baseball, Mantle was an all-around athlete at Commerce High School, playing basketball and football. He excelled in football, playing the halfback position. After graduating, Mantle was offered a football scholarship by the University of Oklahoma but declined it at his father's behest. However, in his sophomore year, he sustained an injury during a practice football game which nearly ended his athletic career. He was kicked in the left shin and developed osteomyelitis, an infectious disease incurable just a few years earlier, in his left leg. Mantle's parents drove him overnight to Oklahoma City, where he was treated at a children's hospital with the newly available penicillin. The treatment successfully reduced the infection and saved his leg from amputation.

Later in life, Mantle confided in friends and family about how he suffered from sexual abuse as a child at the hands of his older half-sister Anna Bae, who often babysat her younger half-siblings when Mantle's parents were out, as well as by other adults, including Anna Bae's friends and older boys in the neighborhood. His wife Merlyn recalled later on that Mantle also had a sexual relationship with one of his high school teachers when he was still a minor. According to Merlyn, the teacher "seduced" him: "She just laid over him."

The child sexual abuse he endured at the hands of family and adults likely contributed to Mantle's self-destructive behavior as an adult, with biographer Jane Leavy speculating that Mantle, like many childhood sexual abuse victims, likely suffered from complex post-traumatic stress disorder.

Mantle began his professional baseball career in Kansas with the semi-professional Baxter Springs Whiz Kids. In 1948, Yankees scout Tom Greenwade came to Baxter Springs to watch Mantle's teammate, third baseman Willard "Billy" Johnson. During the game, Mantle hit three home runs. Greenwade returned in 1949, after Mantle's high school graduation, to sign Mantle to a minor league contract with the Yankees at $140 per month (equivalent to $1,800 in 2023), with a $1,500 signing bonus (equivalent to $19,200 in 2023).

Mantle was assigned to the Yankees' Class-D Independence Yankees of the Kansas–Oklahoma–Missouri League, where he played shortstop and hit .313. He hit his first professional home run on June 30, 1949, at Shulthis Stadium in Independence, Kansas. The ball went over the center field fence, which was 460 feet from home plate. In 1950, Mantle was promoted to the Class-C Joplin Miners of the Western Association, where he won the Western Association batting title with a .383 average. He hit 26 home runs and recorded 136 RBIs, but struggled defensively at shortstop.

In July 1950, after the start of the Korean War, Mantle was drafted for military service. The draft board rejected him as physically unqualified for military service due the osteomyelitic condition of his left leg and gave him a 4-F deferment, the first of three times he was rejected for military service.

Mantle was invited to the Yankees instructional camp before the 1951 season and proceeded to make a big impression during spring training. One famous incident was when he hit two home runs at Bovard Field against the USC Trojans baseball team, when the Yankees were on a thirteen-game spring training tour of the west coast. Both home runs, one from each side of the plate, reportedly traveled a distance of at least 500 feet. Impressed by the 19-year-old's power, Yankees manager Casey Stengel decided to promote Mantle to the majors as a right fielder instead of sending him to the minors; his salary for the 1951 season was $7,500. Mantle was assigned uniform No. 6, signifying the expectation from the Yankees front office that he would become the next Yankees star, following Babe Ruth (No. 3), Lou Gehrig (No. 4), and Joe DiMaggio (No. 5).

After a brief slump, Mantle was sent down to the Yankees' top farm team, the Kansas City Blues. His struggles at the plate continued. Out of frustration, he called his father and told him: "I don't think I can play baseball anymore." Mutt Mantle drove up to Kansas City that day. When he arrived, he started packing his son's clothes and, according to Mantle, said: "I thought I raised a man. I see I raised a coward instead. You can come back to Oklahoma and work the mines with me." After his father's rebuke, Mantle gradually broke out of his slump and went on to hit .361 with 11 home runs and 50 RBIs during his stay in Kansas City.

Mantle was called up to the Yankees after 40 games with Kansas City, this time wearing uniform No. 7. He hit .267 with 13 home runs and 65 RBI in 96 games as the Yankees reached the World Series against the New York Giants. In the second game of the 1951 World Series, Giants rookie Willie Mays hit a fly ball to right-center field. Mantle, playing right field, raced for the ball together with center fielder DiMaggio. At the last moment, the latter called for the ball. In attempting to stay out of DiMaggio's way, Mantle's spikes got caught over an exposed drain pipe. His knee twisted awkwardly and he fell instantly, his right knee injured severely. Mantle had to be carried off the field on a stretcher. This was the first of numerous injuries that were to plague his eighteen-year career with the Yankees. He was to play the rest of his career with a torn anterior cruciate ligament (ACL).

Accompanying his son to the hospital after the game, Mantle's father collapsed onto the sidewalk while trying to help his son into a taxi. The two were given hospital beds in the same room and watched the remainder of the World Series together. Mutt Mantle was diagnosed with Hodgkin's disease; he died a few months later at the age of 40, on May 7, 1952. Mantle, at the time away with the Yankees, was informed by manager Stengel of his father's death and was inconsolable.

Following the 1951 World Series, DiMaggio retired from baseball. As a result, Mantle moved to center field before the start of the 1952 season. He played that position full-time for the Yankees until 1965, when he was moved to left field near the end of his career. That year, Mantle was selected as an All-Star for the first time but did not make an appearance in the rain-shortened All-Star Game. The Yankees won the pennant and faced the Brooklyn Dodgers in the World Series. Mantle performed well in the series, recording an on-base percentage above .400 and a slugging percentage above .600. In Game 6, he homered in a 3–2 win. In Game 7, he knocked in the winning runs in the 4–2 victory, with a home run in the sixth inning and an RBI single in the seventh.

Mantle's emergence as a star center fielder coincided with the Korean War. Due to his previous rejection, he was not amongst the baseball players who joined the Armed Forces, leading baseball fans and sportswriters to question his 4-F deferment. This led to newspapers even calling him a "draft dodger" and Mantle receiving threatening letters. In April 1951, Mantle was re-examined by the draft board and was once again rejected as being physically unfit for military service. A second highly publicized physical, brought on by his All-Star selection, was held in October 1952 and ended in a final rejection, this time due to the knee injury sustained in the 1951 World Series.

Mantle had a strong 1953 season, making the All-Star Game and helping the Yankees to another World Series, which they won against the Brooklyn Dodgers. He missed several weeks due to his previously injured knee which had been left untreated after the initial stay in hospital in 1951. After the season ended, a full two years after the injury he had picked up at the 1951 series, Mantle had surgery performed on his left knee in November 1953. The following season, Mantle recorded his first 100-RBI season while also hitting over .300 and leading the league in runs scored. He had a strong season in 1955 as well, leading the AL in home runs, triples, and walks, and recording a .306 batting average.

The 1956 season was, statistically, Mantle's greatest and was later described by him as his "favorite summer." He led the majors with .353 batting average, 52 home runs, and 130 RBIs, winning the Triple Crown, the only switch hitter to do so. This was the first of three AL MVP Awards. He also hit his second All-Star Game home run that season. That year, the Yankees again faced the Brooklyn Dodgers in the World Series. In the fifth inning of Game 5, Mantle kept Don Larsen's perfect game alive by making a running catch of a deep fly ball off the bat of Gil Hodges. The inning before, he had scored the first of the Yankees' two runs with a home run off Brooklyn starter Sal Maglie. Mantle's overall performance in 1956 led to his being named Associated Press Male Athlete of the Year, and he was also awarded the Hickok Belt as the top American professional athlete of the year.

Mantle won his second consecutive MVP in 1957, leading the leagues in runs scored and walks and recording a career-high batting average of .365, second best in the AL. That season, Mantle reached base more times than he made outs (319 to 312), one of two seasons in which he achieved the feat. In the 1957 World Series, the Yankees faced the Milwaukee Braves. During Game 5, Mantle suffered a torn tendon in his left shoulder from a collision with Braves second baseman Red Schoendienst. The Braves won the series in seven games and the injury would lead to Mantle having struggles in his uppercut swing from the left side for the remainder of his career.

Still recovering from his shoulder injury, Mantle's 1958 season started slowly; during the first half, he was hitting a modest .274. He eventually regained his form, hitting .330 in the second half of the season, finishing with .304 batting average and leading the league in home runs, runs scored, and walks. He led the Yankees back to a World Series rematch against the Braves, this time coming out victorious. Despite his strong season, the Yankees declined Mantle's request for a contract raise to $85,000, citing that his batting average was almost 61 points lower than the year before. After briefly holding out, Mantle eventually settled for their lower offer of $70,000.

In the 1959 season, as the Yankees finished third in the AL rankings, Mantle's overall numbers declined from the previous season. He recorded only 75 RBIs and also racked up a league-leading 126 strikeouts. Though he led the team in base stealing (23), runs scored (104), on-base percentage (.390), and fielding percentage (.995), Mantle agreed to take a salary cut of $10,000 at the end of the season. The 1959 season was also the first of four consecutive seasons when two All-Star games were played, with Mantle playing in seven of these games. Mantle made the All-Star team as a reserve player in 1959. In the first game, he was used as a pinch runner and as replacement right fielder. In the second game, Mantle was the starting center fielder, recording a single and a walk in four at-bats.

Mantle began the 1960 season slowly, with his batting average dropping as low as .228 in June. However, he regained his form and finished the season leading the AL in home runs and runs scored, as the Yankees won the pennant. That year, Mantle started in both All-Star games, getting two walks in the first and a single in the second. Although his batting average was the lowest since his rookie year, a league-leading 40 home runs and 94 RBIs saw him come a close second to teammate Roger Maris in the MVP race. In the 1960 World Series against the Pittsburgh Pirates, Mantle turned in his best performance in a single postseason. In seven games, he batted .400 (10-for-25) with 9 walks, hitting three home runs with 11 RBIs and recording an on-base percentage of .545. The Yankees lost the World Series in Game 7 on Bill Mazeroski's walk-off home run. Mantle was devastated by the loss, reportedly crying in the clubhouse afterwards. He would later call the loss in the 1960 World Series as one of the biggest disappointments of his career.

During the 1961 season, Mantle and teammate Roger Maris, known as the M&M Boys, pursued Babe Ruth's 1927 single-season record of 60 home runs. Five years earlier, Mantle had challenged Ruth's record for most of the season, and the New York press had been protective of Ruth on that occasion. When Mantle finally fell short, finishing with 52 home runs, many reporters were relieved. The New York press was harsh in its treatment of Mantle in his early years with the Yankees, emphasizing that he struck out frequently, was injury-prone, was a rube from Oklahoma, and was perceived as inferior to DiMaggio. Over time, however, Mantle had learned to deal with the New York media and had gained the favor of the press, receiving help from teammate Whitey Ford, a native of Queens.

Unlike Mantle, Maris was new to the New York scene, having been traded to the Yankees from the Kansas City Athletics before the 1960 season, and never managed to adjust to demands of the New York press, many of whom began to view him as surly and rude. During the 1961 season, the press pushed the notion of the Yankees being Mantle's team, with Maris often belittled and ostracized as an outsider and not a "true Yankee".

Late in the season, Mantle was hospitalized with a severe abscessing septic infection on his hip, which had resulted from a "miracle shot" that he had received from physician Max Jacobson at the recommendation of Yankees broadcaster Mel Allen. It was discovered years later that Jacobson's so-called "miracle shot" was in fact laced with various substances, including amphetamines and methamphetamines, and resulted in at least one death. This revelation exposed Jacobson as a fraud and he was stripped of his medical license in 1975.

While Maris went on to break the record on the last day of the season, Mantle finished with 54 home runs, the single-season record for a switch-hitter. He also led the AL in runs scored and walks. For the second consecutive year, he narrowly missed winning his third MVP award, finishing second to repeat winner Maris. Under new manager Ralph Houk, the Yankees won the World Series that year against the Cincinnati Reds. Neither Mantle nor Maris performed well in the series, recording between them three hits and two RBIs in twenty-five at-bats over five games.

In 1962, Mantle batted .321 in 121 games and was selected as an All-Star for the eleventh consecutive season. He played in the first game but, due to the recurrence of an old injury, sat out the second. Despite missing 41 games, he was selected as MVP for the third time, beating out teammate Bobby Richardson in the voting. With a .978 fielding percentage that season, he also received his only Gold Glove Award. In the 1962 World Series, the Yankees beat the San Francisco Giants in seven games. Mantle fared poorly in the series, hitting .120 with five strikeouts. After the 1962 season, the Yankees gave Mantle a contract of $100,000, making him the fifth player to reach that pinnacle, after Hank Greenberg, Joe DiMaggio, Ted Williams, and Stan Musial (1958 and 1959). Only Willie Mays, with a salary of $105,000, made more than Mantle in 1963. Having reached the $100,000 salary threshold, Mantle never asked for another raise.

On May 22, 1963, Mantle hit a long drive off the top of the right field facade at Yankee Stadium, the closest that anyone came to hitting a home run out of the old stadium. However, on June 5, he broke his foot while trying to prevent a home run by Brooks Robinson in Baltimore; his spikes had been caught in the center field chain-link fence as he came down after leaping against it. As a result, he did not play again until August 4, when he hit a pinch-hit home run against the Baltimore Orioles at Yankee Stadium. Mantle returned to the center field position on September 2 and finished the season batting .314 in 65 games. He was selected as an All-Star but, due to the foot injury, did not make the AL 25-man roster for the first time.

That year, the Yankees made the World Series and were favorites to win over the Los Angeles Dodgers. They were swept in four games for the first time in franchise history. In Game 1, Mantle struck out twice against Cy Young Award winner and National League MVP Sandy Koufax, who finished with a record-setting 15 strikeouts in a World Series game. In Game 4, he hit a home run off Koufax to tie Babe Ruth's record of 15 in the World Series. With the tying run on base in the ninth inning, he struck out against Koufax for the third time. He finished the series 1-for-15 with five strikeouts.

In 1964, Mantle hit .303 with 35 home runs and 111 RBIs, and played center field in the All-Star game. He finished in second place in the MVP voting. The Yankees faced the St. Louis Cardinals in the 1964 World Series. In the bottom of the ninth inning of Game 3, Mantle hit a walk-off home run into the right field stands at Yankee Stadium to win the game for his team by a score of 2–1. This was his 16th home run in the World Series, breaking Ruth's record of 15. He hit two more home runs in the series to set a new record of 18, including an opposite field shot off Cardinals star Bob Gibson in St. Louis, and hit .333 with 8 RBIs overall. Despite Mantle's performance, the Cardinals won the World Series in seven games behind Gibson's overall excellent pitching.

On April 9, 1965, the Houston Astros and the Yankees played an exhibition game to inaugurate the Astrodome, the world's first multi-purpose, domed sports stadium. In the sixth inning Mantle hit the park's first home run. By 1965, he and the aging Yankees were slowed by injuries, finishing sixth in the AL rankings. Mantle hit .255 with 19 home runs and 46 RBI in 361 plate appearances. He was again selected as an All-Star, this time as a reserve player, and did not make an appearance in the game.

In 1966, Mantle's batting average increased to .288 with 23 home runs and 56 RBI in 333 at-bats. This improvement was largely due to strong performances in June and July, when he returned to his normal form until sidelined with another injury. After the 1966 season, he was replaced by Joe Pepitone in the outfield, and spent his final two seasons at first base. On May 14, 1967, Mantle became the sixth member of the 500 home run club.

Mantle hit .237 with 18 home runs and 54 RBIs during his final season in 1968. As a result, his lifetime average was to dip below .300, which caused him a lot of anguish. That year, despite his lowly numbers, Mantle was selected as an All-Star and made an appearance as a pinch-hitter at the All-Star Game at the Astrodome.

Mantle announced his retirement at the age of 37 on March 1, 1969. He delivered a farewell speech on Mickey Mantle Day, June 8, 1969, at Yankee Stadium. Mantle's wife, mother, and mother-in-law were in attendance and received recognition at the ceremony held in his honor. When he retired, Mantle was third on the all-time home-run list with 536, and he was the Yankees' all-time leader in games played with 2,401, a record that would be broken by Derek Jeter on August 29, 2011.

In his career, Mantle batted .298 with an on-base percentage of .421 and an on-base plus slugging percentage of .997. He accumulated 2,415 hits, including 536 home runs, 344 doubles, and 72 triples. While Mantle led the league in strikeouts five times, holding the all-time record at the time of his retirement, he was also adept at drawing walks. He led the majors in walks five times and finished with at least 100 walks in a season ten times. As an outfielder, he recorded a career fielding percentage of .982.

Mantle was selected as an All-Star every season during his 18-year career except for 1951 and 1966. He was a seven-time World Series champion with the Yankees, playing in twelve overall. In the World Series, he hit .257 over 65 games and holds the all-time World Series records for home runs (18), runs scored (42), and RBIs (40).

Mantle is considered to be one of the greatest switch hitters in baseball history, hitting for both average and for power from both sides of the plate. In particular, he was known for his power, hitting some of the longest home runs in Major League history. On September 10, 1960, he hit a ball left-handed that cleared the right-field roof at Tiger Stadium in Detroit. Based on where the ball was found, it was estimated years later by historian Mark Gallagher to have traveled 643 feet (196 m).

Another Mantle home run, hit right-handed off Chuck Stobbs at Griffith Stadium in Washington, D.C., on April 17, 1953, was measured by Yankees traveling secretary Red Patterson (hence the term tape-measure home run) to have traveled 565 feet (172 m). Deducting for bounces, there is no doubt that each of the above home runs landed well over 500 feet (152 m) from home plate.

Twice in his career Mantle hit a home run off the third-deck facade at Yankee Stadium, nearly becoming the only player to hit a fair ball out of the stadium during a game. On May 22, 1963, against Kansas City's Bill Fischer, Mantle hit a home run against the 110-foot (34 m) high facade, before the ball caromed back onto the playing field. It was later estimated that the ball could have traveled 504 feet (154 m) had it not been blocked by the ornate and distinctive facade. On August 12, 1964, he hit one whose distance was undoubted: a center-field drive that cleared the 22-foot (6.7 m) batter's eye screen, some 75 feet beyond the 461-foot (141 m) marker at Yankee Stadium.

Although Mantle was a feared power hitter from either side of the plate and hit more home runs batting left-handed than right, he was a better hitter overall right-handed: roughly 25% of his total at-bats were from the right side, producing a batting average of .330 as opposed to .281 when batting from the left side. His 372 (left) to 164 (right) home run disparity was due to Mantle having batted left-handed much more often, as a large majority of pitchers are right-handed. In spite of short foul pole dimensions of 296 feet (90 m) to left and 301 feet (92 m) to right in the original Yankee Stadium, Mantle gained no advantage there as his stroke both left and right-handed drove balls to power alleys of 344–407 feet (right center) and 402–457 feet (left center) from the plate. Overall, he hit slightly more home runs away (270) than home (266).

Despite being known for power hitting, Mantle was also regarded as one of the best bunters for base hits. He is in 10th place in number of bases-empty bunt singles, with 80 in only 148 at-bats. He was also known for his remarkable ability to avoid grounding into double plays: for every 100 at-bats, Mantle grounded into 1.40 double plays, one of the lowest marks in history. In both 1953 and 1961, he hit into only two double plays over the course of 1,186 plate appearances.

Though not a flashy fielder, Mantle was an overall solid center fielder, especially considering he did not play the position until after he had reached the Major Leagues. Manager Casey Stengel, unimpressed with him at shortstop, moved him to the outfield before his rookie year. Over time, Mantle developed one of the strongest outfield arms to compensate for weak points in his fielding. His outfield throws discouraged runners from taking an extra base. Possessed of good range in center field, his defensive skill was considered 'the less spectacular equal of his offensive genius'. Although he considered himself a better hitter than fielder, Mantle felt his running catch during Don Larsen's perfect game was the best play of his career. He later referred to it as "probably the only good catch I ever made. I wasn't that good of a fielder."

Mantle's career was plagued with injuries. Beginning in high school, he suffered both acute and chronic injuries to bones and cartilage in his legs. By the end of his career simply swinging a bat caused him to fall to one knee in pain. Baseball scholars often ponder "what if" had Mantle not been injured but able to enjoy a healthy career.

In particular, the torn cartilage Mantle sustained to his right knee during the 1951 World Series was a very serious injury. Witnesses say it looked "like he had been shot." Dr. Stephen Haas, former medical director for the National Football League Players Association, has speculated that Mantle injured his ACL during that incident and played the rest of his career without having it properly treated, since an ACL could not be repaired with the surgical techniques available in that era. Surgery performed in 1953 removed torn cartilage to prevent further erosion to the joint but also left his knee unstable. In order to minimize the effect of that, Yankee trainers would later wrap up his knees tightly with athletic tape. After the injury, teammates noted a change in Mantle's gait and a loss of speed as a result. Despite his bad knee, Mantle was still known as the "fastest man to first base", once reportedly being recorded reaching first base in 3.1 seconds. However, he was forbidden by Yankee managers from base stealing over the worry that his "delicate" knees would break down faster.

Further, the shoulder injury Mantle suffered during the 1957 World Series, while not affecting his numbers, led to increasing difficulty in hitting from the left side over the next decade.

After retiring from baseball, Mantle briefly served as a part-time color commentator for NBC on Game of the Week. In 1969, he was the color commentator for the All-Star Game. He also served as a pre-game analyst for the 1969 and 1970 World Series. He was one of four color commentators used by the Expos during the 1972 season.