Corbin began his career as a Shakespearean actor in the 1960s, but today he is more likely to be seen in the role of the local sheriff, military leader, or some other authority figure, though on occasion, he has effectively portrayed murderous villains as well. To moviegoers he is well remembered as General Beringer in WarGames, John Travolta's uncle in Urban Cowboy, co-starring with Clint Eastwood in Any Which Way You Can, or Roscoe Brown, who was July Johnson's bumbling deputy, in the acclaimed western Lonesome Dove.
He also had a role in 2008's Oscar-winning film No Country for Old Men.
From 1979 until 1984 he appeared in several episodes of "Dallas (TV series)" as Sheriff Fenton Washburn. In 1983, Corbin co-starred in the famed television mini-series The Thorn Birds. Corbin played Mary Carson's stockman "Pete", who teaches the Cleary's sons how to shear sheep on their aunt's gigantic sheep station Drogheda, in Australia. In 1983-1984, Corbin played Merit Sawyer in the NBC television series Boone. Corbin's role was that of a stern father to the young actor Tom Byrd, who played Boone Sawyer, an aspiring singer. The program was set in rural Tennessee during the 1950s and was created by Earl Hamner, who had great success earlier with CBS's The Waltons. From 1990 to 1995, Corbin portrayed former astronaut Maurice Minnifield on CBS's Northern Exposure, for which he received an Emmy nomination.
In 1994, Corbin narrated the acclaimed TBS documentary MoonShot, telling the story of the 1960s space race from the first-person viewpoint of Mercury Seven astronaut Deke Slayton. In 2007, He played the character Clay Johnson, father of Deputy Chief Brenda Leigh Johnson on The Closer series.
From 2003-2008, Corbin was a cast member of the teenage drama series One Tree Hill, where he portrayed a basketball coach for the Tree Hill Ravens. Corbin lost most of his hair in the 1990s due to alopecia areata. Since then, he has played various roles with a shaved head, wearing a cowboy hat, or occasionally wearing a full toupee. Corbin is the signature voice of radio station KPLX in Fort Worth, Texas, and has also voiced trailers and promos for CMT and various other country radio stations.