McDougald played his first major league game on April 20, 1951. On May 3 of that year, he tied a major league record, since broken, by batting in six runs in one inning. Later in the year, in the World Series, he became the first rookie to hit a grand slam home run in the Series. He narrowly beat out Minnie Miñoso in the voting for the 1951 American League Rookie of the Year. His entire major league career was spent on the New York Yankees. He was a versatile player, playing all the infield positions except first base: 599 games at second base, 508 games at third, and 284 at shortstop. He was an All-Star in , , , , and , playing in four of the six games that were played (two All-Star games were held in 1959).