The daughter of actress Nan Kelly Yorke, she first modeled while still a baby, then went on to play child roles onstage and in over 50 silent films of the '20s. She worked for a time on radio, then returned to films at 17, going on to play leads in both A- and B-movies over the next decade. With her film work drying up she returned to the stage and won a Tony Award and two Sarah Siddons Best Actress Awards. She appeared in only two more films, one of which was the screen version of The Bad Seed (film, 1956), the play for which she'd won her Tony Award; for her work in the film she received a Best Actress Oscar nomination. She continued a successful stage career through the '70s, and occasionally appeared in TV roles. From 1941-42 she was married to actor Edmond O'Brien. Her brother is actor Jack Kelly.