Her job as an elevator operator at Saks Fifth Avenue brought her in contact with people who worked with films,[2] and she signed with RKO Studios when she was 18 years old.

[3] O'Hara's figure led to her role in Ghost Ship, as the result of a process that was featured in the September 13, 1943, issue of Life.

[5] During World War II, she received the Support for America award, acknowledging her wartime efforts with the Hollywood Canteen.

[3] She also appeared in several TV series during the 1950s, including Fireside Theatre, Gunsmoke, The Millionaire, Racket Squad and Dragnet.

In 1973, she played Mrs. Malone, a night school teacher, on the season four episode "Two Wrongs Don't Make a Writer" on The Mary Tyler Moore Show.