Susan Clark began her acting career as early as 1952. Her family moved to Toronto soon after where she joined the Toronto Children's Player Theatre. She later graduated from the Royal Academy of Dramatic Arts in London, England.
Clark made guest appearances on the television series Run for your Life, Columbo and Murder, She Wrote among others, and had a recurring role on Webster from 1983 to 1989 for which she received a Golden Globe nomination. Her portrayal of Babe Didrickson in the TV movie Babe earned her an Emmy Award in 1975.
Film credits include Madigan, Tell Them Willie Boy is Here, Coogan's Bluff and Colossus: The Forbin Project.
Susan Clark was married to actor Robert L. Joseph from 1970 to 1973 and then to actor Alex Karras from 1980 until his death in 2012. She had a daughter named Katie with Karras. Clark is the stepsister of Linda Thorson who had a recurring role on Emily of New Moon as well.