Griffith took control of the American League's Washington Senators baseball team in 1955, after the death of his uncle and adoptive (or foster, sources differ) father, the player-owner-manager Clark Calvin Griffith (1869-1955). He moved the club to Minneapolis-St. Paul in 1960, as the Minnesota Twins. In 1984 he and his sister sold their interests in the club, ending 72 years of Griffith family ownership.