Alexander Joy Cartwright Jr. was a founding member of the New York Knickerbockers Base Ball Club in the 1840s. Although he was an inductee of the Baseball Hall of Fame and he was sometimes referred to as a "father of baseball", the importance of his role in the development of the game has been disputed.

The New York Knickerbockers were one of the first organized baseball teams which played under a set of rules similar to the game today. Founded as the "Knickerbocker Base Ball Club" by Alexander Cartwright in 1845, the team remained active until the early 1870s.