She is best known for her roles as the heroin addict Helen in the romantic drama The Panic in Needle Park (1971), for which she won the Best Actress award at the 1971 Cannes Film Festival, and her recurring role of Sharon Spencer in the horror film franchise The Exorcist.
[2] Winn traveled widely during much of her childhood, having spent time in the United States, England, Germany, China, India, and Japan.
Winn's career has spanned a wide range of dramatic productions on stage, in motion pictures and on television.
Shortly after college she joined the company at American Conservatory Theater in San Francisco, where she remained for four years under the artistic direction of William Ball.
For this performance, she was nominated for a best actress award by the San Francisco Bay Area Theatre Critics Circle.