[4] Bannon won a screen test and a contract with Warner Bros. after entering a local beauty contest in 1933.

She appeared Gold Diggers of 1933 and Advice to the Lovelorn (1933) soon after, followed by Broadway Melody of 1936,[7] The Great Ziegfeld (1936), One in a Million (1936), and The Flying Deuces (1939).

[9] Bannon was mostly seen in small roles, often as chorus girls, in films in the 1940s, including Lillian Russell (1940),[10] Sis Hopkins (1941), The Great American Broadcast (1941), Dance Hall (1941), Week-End in Havana (1941), Tales of Manhattan (1942), The Black Swan (1942), Sweet Rosie O'Grady (1943), Four Jills in a Jeep (1944), Pin Up Girl (1944), In the Meantime Darling (1944),[11][12] The Late George Apley (1947), Carnival in Costa Rica (1947), Nightmare Alley (1947), Adam's Rib (1949), and The Damned Don't Cry (1950).

Her first husband was film director Charles Faye; they married in 1934 and divorced in 1936.

[18][19] In 1945, she was rumored to be engaged to marry war correspondent Philip Andrews.