Conversation so far:
When did Sinatra debut?
Sinatra made his film debut in 1941, performing in an uncredited sequence in Las Vegas Nights, singing "I'll Never Smile Again" with Tommy Dorsey's The Pied Pipers.
When did he hit his slump?
The New York World Telegram and Sun ran the headline "Gone on Frankie in '42; Gone in '52".
What musical films was Sinatra in?
In 1945, Metro-Goldwyn-Mayer cast Sinatra opposite Gene Kelly and Kathryn Grayson in the Technicolor musical Anchors Aweigh, in which he played a sailor on leave in Hollywood for four days.
Did he win any awards or honors for his movies?
and the song "I Fall in Love Too Easily", sung by Sinatra in the film, was nominated for the Academy Award for Best Original Song.
What other films was Sinatra in?
Take Me Out to the Ball Game, a film set in 1908, in which Sinatra and Kelly play baseball players who are part-time vaudevillians.
Was he in any other films?
The following year he was given his leading roles in Higher and Higher and Step Lively for RKO Pictures.

Question: When did his slump begin?
Self-contained rewrite: When did Frank Sinatra's slump begin?