The Rookie of the Year Award has a chaotic history. Arising from a Chicago BBWAA chapter award begun in 1940, it went national in 1947, officially named the J. Louis Comiskey Memorial Award after the former White Sox executive who was the son of Hall of Famer Charles Comiskey. The first winner was Jackie Robinson; during the fortieth-anniversary celebration of his career in 1987, the award was renamed the Jackie Robinson Award. It has been presented to the top rookie in each league since 1949, after being given to only one player in both 1947 and 1948.
It took ten years before “rookie” was officially defined, and the definition would change twice; in 1989 it stands as a player who has not, in previous seasons, had 130 at-bats, 50 innings, or 45 days on a major league roster. The voting structure has also changed several times; it currently consists of two writers for each team voting for three players each with votes weighted 5-3-1.