Her film debut in Our Town in 1940 saw her receiving an Academy Award nomination for Best Actress.
She never again achieved such acclaim, although she appeared in such films as The Howards of Virginia, The Desperate Hours, The Ten Commandments, Sayonara, Ben-Hur, Airport 1975 and The Turning Point. In both The Ten Commandments and Ben-Hur, she played Charlton Heston's mother.
In 1968 she joined Henry Fonda and Robert Ryan in forming a theatrical production company called The Plumstead Playhouse. It later became the Plumstead Theatre Company and moved to Los Angeles, California. The company produced such fare as First Monday in October, both on stage and in film. Scott co-producer of both versions. Her last production was a performance of Twelve Angry Men, which was performed at the Henry Fonda Theatre in Hollywood. Scott has a star on the Hollywood Walk of Fame, next to the Fonda Theatre.