Major League Baseball

Founding and early rival leagues

The origins of professional baseball trace to the National Association of Professional Base Ball Players, formed in 1871, which included early franchises that later became the Chicago Cubs and Atlanta Braves. This league proved ineffective, leading to the establishment of the National League of Professional Base Ball Clubs in 1876, an event often marked by its first game on April 22, 1876, at the Jefferson Street Grounds in Philadelphia. The NL's early years were marked by instability, with teams frequently folding and rival leagues emerging, and it was not until the 1882 season that the league's membership remained unchanged from the year before. The two leagues occasionally met in a postseason championship series, a precursor to the modern World Series, before merging into a single 12-team National League in 1892. After the NL dropped four teams following the 1899 season, the minor Western League, under president Ban Johnson, renamed itself the American League for the 1900 season and declared itself a major league competitor in 1901. This sparked a fierce bidding war for players, leading to widespread contract-breaking and legal challenges until the conflict was resolved by the National Agreement of 1903, which established peace between the leagues and formalized the reserve clause binding players to their teams. MLB officially recognizes several other early leagues as major, including the American Association, Union Association (1884), Players' League (1890), and Federal League (1914 to 1915). In a landmark decision in December 2020, MLB also recognized seven Negro leagues from 1920 to 1948 as major leagues, integrating their statistics into the official historical record in May 2024.

The dead-ball era and scandal

The period from 1900 to 1919 is known as the dead-ball era, characterized by low-scoring games dominated by pitchers like Walter Johnson, Cy Young, Christy Mathewson, and Grover Cleveland Alexander. The baseball itself, made with less tightly wound American wool rather than modern Australian wool, did not travel as far, and balls were kept in play until they became soft, mangled, and stained with tobacco juice, grass, and mud. Large ballpark dimensions, such as the 635-foot centre field fence at Boston's Huntington Avenue Grounds, and the legal use of trick pitches like the spitball further suppressed offense, making strategies like bunting, stolen bases, and the hit-and-run play paramount. A key rule change, the adoption of the foul strike rule by the NL in 1901 and the AL in 1903, drastically reduced scoring by counting foul balls as strikes, whereas previously batters could foul off unlimited pitches with no penalty. The era ended in scandal following the 1919 World Series, when eight members of the Chicago White Sox were found to have conspired to intentionally lose the series to the Cincinnati Reds in exchange for payments totalling $100,000. Despite being acquitted in court, all eight players, including Shoeless Joe Jackson and Eddie Cicotte, were permanently banned from baseball by the first commissioner, Kenesaw Mountain Landis, who was appointed in 1920 to restore the sport's integrity after the relatively weak National Commission was replaced.

Growth, depression and wartime survival

Baseball's popularity surged in the 1920s, aided by the end of the dead-ball era, which was accelerated by the tragic death of Cleveland's Ray Chapman from a pitched ball in 1920, the only MLB player to die from an on-field injury. The league mandated cleaner, newer white baseballs whenever a ball became scuffed, and the power hitting of Babe Ruth, who hit a then-record 60 home runs in 1927 after having broken the previous record of 29 just eight years earlier, revolutionized the game. The New York Yankees emerged as a dynasty, appearing in their first World Series in 1921 and in 11 total by the end of the 1930s, winning eight of them. The Great Depression of the 1930s severely impacted attendance and profits, with only two MLB teams turning a profit in 1932 as a 10% federal amusement tax on tickets further discouraged fans. Owners responded by cutting rosters from 25 to 23 men, reducing player salaries, and introducing innovations like night games, live radio broadcasts, and promotions such as free admission for women. Remarkably, no MLB team folded or relocated during the economic crisis, unlike major leagues in other sports. World War II posed another challenge, as over 500 men left MLB teams to serve in the military, with many playing on service teams to entertain personnel. Teams fielded rosters with young men, older players, those classified 4F as unfit for service, and unique talents like one-armed outfielder Pete Gray, though black players remained excluded. With a personal plea from Commissioner Landis and the written 'Green Light Letter' support of President Franklin D. Roosevelt, who stated he felt it best for the country to keep baseball going for recreation and morale, the league continued operations throughout the war despite wartime blackout restrictions that limited night games.

Integration and expansion

The racial integration of MLB began with Brooklyn Dodgers executive Branch Rickey's 'Noble Experiment.' He signed Jackie Robinson from a list of promising Negro league players, obtaining a commitment from Robinson to avoid retaliation against racial abuse for a contract of $600 a month, and placed him with the Dodgers' farm club, the Montreal Royals of the International League, for the 1946 season. Robinson broke the major league colour barrier on April 15, 1947, making his debut at Ebbets Field before a crowd of 26,623 spectators, including over 14,000 black patrons who began flocking to see the Dodgers when they came to town, abandoning the Negro league teams they had followed. He endured significant hostility, including a strike threat by some players that was quashed by NL president Ford C. Frick and Commissioner Happy Chandler, who stated any striking players would be suspended, but was supported by teammates like Pee Wee Reese and won the inaugural Rookie of the Year Award. His success paved the way for others, including Larry Doby, who integrated the American League with the Cleveland Indians less than three months later in 1947, and stars like Satchel Paige, Roy Campanella, and Don Newcombe, who later became the first winner of the Cy Young Award. The post-war era also saw significant geographical change, as from 1903 to 1952, all 16 teams were located in ten northeastern and midwestern U.S. cities, with St. Louis as the southernmost and westernmost point. This changed in the 1950s and 1960s as teams began relocating to new cities, and the league started a major expansion that would eventually see the league grow from 16 to 30 franchises over several decades.

The expansion era for Major League Baseball began in the 1960s with the addition of eight new clubs. The American League and National League added two teams in 1961 and another two in 1962. Four more clubs were added in 1969. This period of growth increased the total number of teams in the league.

• 1961: Los Angeles Angels and a new Washington Senators team (replacing the original Senators who moved to Minnesota).
• 1962: Houston Colt .45s (later Astros) and New York Mets.
• 1969: Kansas City Royals, Seattle Pilots (who moved to Milwaukee in 1970), San Diego Padres, and Montreal Expos (the first Canadian team).

Modern era and labour relations

The modern era of MLB has been defined by labour strife, significant on-field changes, and off-field controversies. Player discontent with the restrictive reserve clause led to the organization of the strong Major League Baseball Players Association to collectively bargain with owners. The 1970s and 1980s saw the introduction of modern, multi-purpose stadiums, many with artificial turf surfaces like Toronto's SkyDome, which altered the style of play by creating faster infields. Home run hitting became increasingly dominant in the 1990s, a trend that continued into the 2000s amid the steroid scandal that saw media reports and the subsequent Mitchell Report (2006-07) find widespread use of anabolic steroids and other performance-enhancing substances, including at least one player from each team. On the business side, MLB has grown into a global enterprise, overseeing Minor League Baseball, jointly managing the World Baseball Classic with the World Baseball Softball Confederation, and operating developmental leagues like the Arizona Fall League and the MLB Draft League. By the mid-2020s, MLB was the third-wealthiest professional sports league globally by revenue, behind the National Football League and the National Basketball Association, which surpassed MLB to become number two in 2026. The 2025 season saw total attendance reach 71.4 million, the highest of any sports league in the world, with games broadcast on television, radio, and the internet throughout North America and in several other countries.

League structure and season format

Major League Baseball is composed of 30 clubs, 29 in the United States and one in Canada (the Toronto Blue Jays). The teams are divided equally into two leagues: the American League (AL) and the National League (NL), each further split into three divisions (East, Central, West). The standard regular season consists of 162 games per team, beginning with Opening Day in late March or the first week of April. The postseason tournament involves 12 teams: six from each league, comprising the three division winners and three wild-card teams with the next-best records. The playoffs are a four-round tournament culminating in the World Series, a best-of-seven contest between the AL and NL champions to determine the MLB champion, first played in 1903. The league is headquartered in New York City and is led by the commissioner of baseball, a position created in 1920 with near-unlimited authority over the sport following the Black Sox Scandal.

Notable records, achievements and governance

MLB history is filled with significant team and individual records that define the sport's legacy. The New York Yankees hold the record for most World Series championships with 27, while the reigning champions as of 2025 are the Los Angeles Dodgers. On the individual side, records set during different eras stand as milestones, such as Babe Ruth's single-season home run record of 60 set in 1927, which symbolized the end of the dead-ball era. The career and single-season records for hits, home runs, pitching wins, and strikeouts are pursued by each new generation of players, with the integration of Negro league statistics in 2024 adding the accomplishments of stars like Josh Gibson to the official canon. The league also honours annual achievements with major awards, including the Most Valuable Player, Cy Young Award for pitching, and Rookie of the Year Award, which was first won by Jackie Robinson in 1947 before separate AL and NL awards were created in 1949. MLB governance has evolved from the early National Commission to the powerful commissioner's office, which now oversees not only the major leagues but also the broader baseball ecosystem including the minor league classification system refined by Branch Rickey. The league's ability to endure challenges like the Great Depression and World War II without team foldings, manage labour disputes leading to free agency, and address scandals like the steroid era demonstrates its complex administrative history.

Historical attendance and financial data

Major League Baseball has consistently maintained strong attendance figures throughout its history, adapting to economic and social challenges. During the Great Depression, despite a significant drop in attendance due to economic hardship and a federal amusement tax, no teams folded, and innovations like night games helped sustain fan interest. The integration era beginning in 1947 attracted new audiences, as black fans in large numbers began attending major league games, often abandoning the Negro league teams they had previously supported. By 2025, MLB achieved its highest total season attendance of any sports league in the world, drawing 71.4 million spectators across its 30 ballparks. Financially, MLB has grown into a massive enterprise, though its relative position among leagues has shifted. However, by the mid-2000s, it was surpassed in revenue by the National Football League (NFL). In 2026, the National Basketball Association (NBA) also surpassed MLB in revenue, making MLB the third-wealthiest professional sports league globally. This financial growth is supported by extensive television and digital media rights, merchandise sales, and international events like the World Baseball Classic.

Questions about Major League Baseball

How many teams are in Major League Baseball?

Major League Baseball consists of 30 teams. Twenty-nine are based in the United States and one, the Toronto Blue Jays, is based in Canada. The teams are split evenly into two leagues: the American League and the National League, each with 15 clubs. Each league is further divided into three geographic divisions: East, Central, and West.

What was the Black Sox Scandal?

The Black Sox Scandal was a game-fixing conspiracy that rocked baseball after the 1919 World Series. Eight players from the American League champion Chicago White Sox, including Shoeless Joe Jackson and Eddie Cicotte, were accused of intentionally losing the series to the National League's Cincinnati Reds in exchange for payments from gamblers totalling $100,000. Although acquitted in a criminal trial in 1921, all eight players were permanently banned from professional baseball for life by the first commissioner, Kenesaw Mountain Landis. The scandal led to the dissolution of the National Commission and the establishment of a powerful, single commissioner's office to oversee the sport's integrity.

Who was the first black player in Major League Baseball?

Jackie Robinson broke baseball's colour barrier on April 15, 1947, when he started at first base for the Brooklyn Dodgers at Ebbets Field. He was selected by Dodgers executive Branch Rickey and had spent the 1946 season preparing with the Montreal Royals, the Dodgers' top minor league affiliate in the International League. Robinson faced immense racial hostility but succeeded, winning the inaugural Major League Baseball Rookie of the Year Award. His courage paved the way for the integration of the sport, with Larry Doby joining the Cleveland Indians of the American League later that same July.

What is the World Series?

The World Series is the annual championship series of Major League Baseball, a best-of-seven playoff between the champions of the American League and the National League. It has been contested almost every year since 1903, following the National Agreement that ended the league war. The series is played in October, concluding the MLB postseason which expanded to include 12 teams in recent years. The New York Yankees hold the record for the most World Series championships with 27. The reigning champions as of 2025 are the Los Angeles Dodgers, who defeated the Toronto Blue Jays four games to two.

When did the Toronto Blue Jays join MLB?

They were part of the league's expansion era, which saw the addition of several new teams. This era included earlier expansions in 1961, 1962, and 1969. The Blue Jays are one of the 30 teams in MLB, which is divided equally between the American League and the National League. They are one of the 29 teams based in the United States and one team based in Canada.

How long is the MLB regular season?

Each Major League Baseball team plays 162 games per regular season. This schedule begins with Opening Day, which is held during the last week of March or the first week of April. The season runs through the fall, leading into the postseason tournament in October. Following the regular season, six teams from each league advance to a four-round playoff. This playoff culminates in the World Series, a best-of-seven championship series first played in 1903.

Sources and further reading

• Major League Baseball (Wikipedia)
• 30 MLB Teams: Location, Stadium and Website Information (mlb.com)
• List of all the Major League Baseball Teams (baseball-reference.com)
• MLB News, Major League Baseball Scores, Schedule ... (nytimes.com)

Checked by the Garbutt Disposal desk. Last updated 2026-10-18.