He replaced Jim Varney as the voice of Slinky Dog in Toy Story 3 and appeared as a biker in the film Bedtime Stories. He played Harry Turner in 24 episodes of Home Improvement. He also had a recurring role on the Disney-produced sitcom Boy Meets World from seasons 2 to 7 as Chet Hunter, the father of Shawn Hunter (portrayed by Rider Strong). He also played Farmer Fern in The Waterboy. Clark portrayed Uncle Mel in Good Luck Charlie.
- He was really good friends with Jim Varney in real life and in an interview for Toy Story 3, he described Varney as a very good friend and man.