Musical director for MGM during its golden age of movie musicals. His trademark was wearing a captain's hat when he played.
He was nominated for six Academy Awards: for 'The Harvey Girls' from 1946 and 'The Pirate' from 1948, both starring Judy Garland, 'On the Town' from 1950, for which he won the Academy Award, 'Singin' in the Rain' from 1952, 'Star!' from 1968, and 'Hello, Dolly!' from 1969, for which he won his second Oscar.
He married famous singer and actress Lena Horne in 1947. She admitted years after his death to having married him to advance her career, but said that she developed a love for him.
He arranged the George Harrison song "Something," for Frank Sinatra in 1970, although Sinatra ultimately opted to use a Nelson Riddle version of it.