Jackie Robinson, the first African American to break the baseball color line, played his first game in Major League Baseball.

Jack Roosevelt Robinson was an American professional baseball player who became the first Black American to play in Major League Baseball (MLB) in the modern era. Robinson broke the color line when he started at first base for the Brooklyn Dodgers on April 15, 1947. The Dodgers signing Robinson heralded the end of racial segregation in professional baseball, which had relegated black players to the Negro leagues since the 1880s.

African Americans, also known as Black Americans and formerly called Afro-Americans, are an American racial and ethnic group who as defined by the United States census, consists of Americans who have ancestry from "any of the Black populations of Africa". African Americans constitute the second largest racial and ethnic group in the U.S. after White Americans. The term "African American" generally denotes descendants of Africans enslaved in the United States. According to annual estimates from the U.S. Census Bureau, as of July 1, 2024, the Black population was estimated at 42,951,595, representing approximately 12.63% of the total U.S. population.

The color line, also known as the color barrier, in American baseball excluded African American players from Major League Baseball and its affiliated Minor Leagues until 1947. Racial segregation in professional baseball was sometimes called a gentlemen's agreement, meaning a tacit understanding, as there was no written policy at the highest level of organized baseball, the major leagues. A high minor league's vote in 1887 against allowing new contracts with black players within its league sent a powerful signal that eventually led to the disappearance of blacks from the sport's other minor leagues later that century, including the low minors.

Major League Baseball (MLB) is a professional baseball league in North America composed of 30 teams, divided equally between the National League (NL) and the American League (AL), with 29 in the United States and 1 in Canada. MLB is one of the major professional sports leagues in the United States and Canada and is considered the premier professional baseball league in the world. Each team plays 162 games per season, with Opening Day held during the last week of March. 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. MLB is headquartered in Midtown Manhattan.