Wilcox may be best known for her role in To Kill a Mockingbird (1962), in which she played Mayella Violet Ewell, whose father falsely claimed she had been raped by a black man, which sparks the trial at the center of the film.

[1] Wilcox made her professional debut in Chicago as part of the improvisational group, The Compass Players,[1] which included Mike Nichols, Elaine May, and Shelley Berman.

Playing opposite Richard Basehart, Kevin McCarthy, and William Hansen, Wilcox won the Clarence Derwent Award for her performance in The Day The Money Stopped[2] by Maxwell Anderson and Brendan Gill, which lasted only three nights on Broadway in 1958.

A life member of The Actors Studio,[3] Wilcox is perhaps best known for her role in the 1962 film To Kill a Mockingbird, in which she played Mayella Violet Ewell, who falsely accuses Tom Robinson (Brock Peters) of raping her.

She recalled receiving "unfriendly looks" when she showed up at an NAACP conference in Monterey, California, because in the film To Kill a Mockingbird, she played a white woman who falsely accused Tom Robinson, a black man, of raping her.