
In December of 1940 Darryl F. Zanuck, President of 20th Century Fox, offered Carole a seven year contract at the studio. The press predicted that he was going to make her a star like he had done for Betty Grable and Alice Faye. Zanuck said "I figured any girl who is so popular with men, whom so many men want to date, must have something we can use and need in our pictures." Carole's first film at Fox was the Technicolor musical Moon Over Miami. Next she costarred with Cesar Romero in Dance Hall and got top billing in the musical Cadet Girl. Director Rouben Mamoulian wanted her to star in his drama Blood and Sand. Carole turned down the part and rumors started that she had refused to dye her hair for the role. Darryl Zanuck had a reputation as a sexual predator who slept with all the actresses at Fox. Carole did have a sexual relationship with him and gossip about their affair hurt her reputation. When she stopped giving in to Zanuck's sexual demands he was furious.

Then she was cast in the B-movie Behind Green Lights. She hated the script and said it became her least favorite role. When she was assigned a bit part in Somewhere In The Night she refused to do it. Carole said "it would be detrimental to my career." Zanuck immediately put her on suspension without pay. After returning to the studio she made the low budget comedy It Shouldn't Happen To A Dog. It would be her last movie at 20th Century Fox. On October 24, 1946 she found out that her contract would not be renewed. Carole told a friend "I feel very happy about this, needless to say, for my last pictures on the lot were pretty dreary." She had been at Fox for six years and despite some success she never became an A-list star. After Carole's death Darryl Zanuck spread lies that she wasn't a good actress and that she slept with everyone at the studio. Unfortunately these lies hurt Carole's legacy and many film historians dismissed her as an untalented B-actress.