Knight appeared as Heavenly Finlay in the 1962 movie Sweet Bird of Youth, based on the Tennessee Williams play in which Paul Newman tries to blackmail an aging actress over her hashish habit. The story is about hypocrisy and corruption, with Knight's character trapped into playing a pure paragon of womanhood by her politician father, and Chance (Newman) desperately trying to break her free. (The play was written for Tokin' Woman Tallulah Bankhead.)
Knight was nominated for an Oscar for her performance in Sweet Bird, one of two nominations she earned while still in her 20s. She won a Tony Award, a Golden Globe, and three Emmys during her career.
Towards the end of her career, Knight played an older woman who gets to enjoy cannabis tea without ramifications in Grandma's Boy (above). In on the fun with Knight are Doris Roberts and Shirley Jones, who beat out her fellow Shirley for the Supporting Actress Oscar in 1961 for her role as a Jezebel in Elmer Gantry; Knight was nominated for The Dark at the Top of the Stairs.
Other notable appearances from Knight include roles in The Group, based on the Mary McCarthy novel; The Divine Secrets of the YaYa Sisterhood; As Good as It Gets where she plays Helen Hunt's mother; Hot in Cleveland as Valerie Bertinelli's mother; and Redwood Highway, a wonderful movie she made in 2013 at the age of 77 about a woman who walks 80 miles to the coast of Oregon. Also in that film are Tom Skerritt, who was so good as the comical motorcycle cop in Harold and Maude, and Sam Daly, who plays the marijuana lobbyist on TV's Madam Secretary.