Gammon may be best-remembered for his characters Lou Brown, manager of the Cleveland Indians in the Major League films, and Nick Bridges, the father of Don Johnson's title character in the television series Nash Bridges. He appeared in the films Cool Hand Luke (1967), Urban Cowboy (1980), Silverado (1985), Noon Wine (1985), The Milagro Beanfield War (1988), Major League (1989), The Adventures of Huck Finn (1993), Major League II (1994), Wyatt Earp (1994), Wild Bill (1995), Truman (1995), Cold Mountain (2003), and more recently Appaloosa (2008). He also had an uncredited role in Natural Born Killers (1994).