In Major League Baseball, the Rookie of the Year Award is given annually to two outstanding rookie players, one each for the American League (AL) and National League (NL), as voted on by the Baseball Writers' Association of America (BBWAA). The award was established in 1940 by the Chicago chapter of the BBWAA, which selected an annual winner from 1940 through 1946. The award became national in 1947; Jackie Robinson, the Brooklyn Dodgers' second baseman, won the inaugural award. One award was presented for all of MLB in 1947 and 1948; since 1949, the honor has been given to one player each in the NL and AL. Originally, the award was known as the J. Louis Comiskey Memorial Award, named after the Chicago White Sox owner of the 1930s. The award was renamed the Jackie Robinson Award in July 1987, 40 years after Robinson broke the baseball color line.

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 leagues, 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.