[1] In the 1960s, she had leading roles in a number of Hollywood films such as The Couch (1962), House of Women (1962), The Group (1966), The Counterfeit Killer (1968), and The Rain People (1969).

In later years, she played supporting roles in many films, including Endless Love (1981), As Good as It Gets (1997), Divine Secrets of the Ya-Ya Sisterhood (2002), and Grandma's Boy (2006).

She trained in acting with Jeff Corey, Erwin Piscator, Lee Strasberg, and Uta Hagen at HB Studio.

[2][3][4] Knight's feature films include The Group (1966), The Dutchman (1967), Petulia (1968), The Rain People (1969), Secrets (1971), Juggernaut (1974), Beyond the Poseidon Adventure (1979), Endless Love (1981), Angel Eyes (2001), Divine Secrets of the Ya-Ya Sisterhood (2002), Paul Blart: Mall Cop (2009), Our Idiot Brother (2011) and Elevator (2011), in which she plays one of several people trapped in a Wall Street elevator with a bomber.

Knight was cast in 1958 and 1959 as Mrs. Newcomb in 20 of the 29 episodes of the television series Buckskin, with Tom Nolan, Sally Brophy, and Mike Road.

[5] A life member of The Actors Studio,[6] Knight's stage credits include Three Sisters (1964), We Have Always Lived in the Castle (1966), Kennedy's Children (1975), which earned her the Tony Award for Best Performance by a Featured Actress in a Play,[7] and A Lovely Sunday for Creve Coeur (1979).

Knight died of natural causes on April 22, 2020, at age 83, at her daughter Kaitlin Hopkins's home in San Marcos, Texas.