Born in London, Ontario on July 18, 1911, Cronyn made his stage debut in 1931 in Up Pops the Devil. He appeared on Broadway in a number of productions ranging from Hipper's Holiday in 1934 to High Tor, A Delicate Balance, and the 1964 Richard Burton Hamlet, for which he won a Tony Award for his role as Polonius. He and his wife of 52 years Jessica Tandy, appeared in a number of productions together, including The Fourposter, The Gin Game, and Foxfire, and were honored with the first Special Tony Award for Lifetime Achievement in 1994. (Tandy died of ovarian cancer in September of that year.)
Cronyn's film performances included the Alfred Hitchcock-directed Shadow of a Doubt and Lifeboat, The Seventh Cross (for which he was nominated for an Academy Award), The Postman Always Rings Twice, Sunrise at Campobello, Brewster's Millions, and both Cocoon films. His many starring television appearances include adaptations of his stage successes The Gin Game and Foxfire and a new version of 12 Angry Men in 1997.
Cronyn is survived by his second wife, Susan Cooper, whom he married in 1996, and two children.