He was nominated for the Academy Award for Best Original Song eleven times and won three Oscars for composing "Lullaby of Broadway", "You'll Never Know" and "On the Atchison, Topeka and the Santa Fe".

Soon he taught himself to play the piano and by 1915, he was working at the Vitagraph Motion Picture Studios, where he did a variety of administrative jobs, such as props man, and also played mood music on the piano for the actors, acted in bit parts and eventually was an assistant director.

[2] His songs eventually appeared in over 300 films and 112 of Warner Bros. Looney Tunes and Merrie Melodies cartoons.

[3] He collaborated on some of his most famous songs with lyricists Al Dubin, Billy Rose, Mack Gordon, Leo Robin, Ira Gershwin and Johnny Mercer.

In 1942 the Gordon-Warren song "Chattanooga Choo-Choo", as performed by the Glenn Miller Orchestra, became the first gold record in history.

[9] Among his biggest hits were "There Will Never Be Another You", "I Only Have Eyes for You", "Forty-Second Street", "The Gold Diggers' Song (We're in the Money)", "Lullaby of Broadway", "Serenade In Blue", "At Last", "Jeepers Creepers", "You're Getting to Be a Habit with Me", "That's Amore", and "Young and Healthy".

In 1930, he composed the music for the song "Cheerful Little Earful" for the Billy Rose Broadway revue, Sweet and Low, and composed the music, with lyrics by Mort Dixon and Joe Young, for the Ed Wynn Broadway revue The Laugh Parade in 1931.

[11] He moved to MGM starting in 1944, writing for musical films such as The Harvey Girls and The Barkleys of Broadway, many starring Fred Astaire.

His "uptempo songs are as memorable as Berkeley's choreography, as [sic] for the same reason: they capture, in a few snazzy notes, the vigorous frivolity of the Jazz Age.

"[12] Warren won the Academy Award for Best Song three times, collaborating with three different lyricists: "Lullaby of Broadway" with Al Dubin in 1935, "You'll Never Know" with Mack Gordon in 1943, and "On the Atchison, Topeka and the Santa Fe" with Johnny Mercer in 1946.

[13] The last musical score that Warren composed specifically for Broadway was Shangri-La, a disastrous 1956 adaptation of James Hilton's Lost Horizon, which ran for only 21 performances.

[18] According to Wilfrid Sheed, quoted in Time magazine: "By silent consensus, the king of this army of unknown soldiers, the Hollywood incognitos, was Harry Warren, who had more songs on the Hit Parade than Berlin himself and who would win the contest hands down if enough people have heard of him.

(1930, with Mort Dixon and Billy Rose for Sweet & Low), "I Found a Million Dollar Baby (in a Five and Ten Cent Store)" (1931, with Dixon and Rose for Crazy Quilt), "You're Getting to Be a Habit with Me" (1932), "Summer Night" (1936), "There Will Never Be Another You" (1942), "Serenade in Blue" (1942), "At Last" (1942), "Jeepers Creepers" (1938), and "The More I See You" (1945).