Karn and his wife, actress Tudi Roche (who periodically appeared on Home Improvement (1991) as one of Jill Taylor's sisters) have one child, a son, Cooper Karn.
Worked as an apartment building manager prior to his success on Home Improvement (1991), and even maintained that job during the show's first season until he knew that Home Improvement (1991) would be successful.
His last name is omitted from his stage name because it was discovered that the Screen Actors Guild already had an actor by the name of Richard Wilson.
His father, Gene, is a retired building contractor. His mother, Louise, was a painter (she died of bone marrow cancer in 1983).
Was not the original actor chosen to be Al on Home Improvement. Stephen Tobolowsky was originally cast and Richard filled in as a favor to the directors in the pilot when Stephen wasn't available. Once Stephen decided to pursue a movie career Richard agreed to stay on as Al.
Karn attended Nathan Eckstein Junior High School and Theodore Roosevelt High School (both in Seattle, Washington). He later graduated from the University of Washington with B.F.A. from the Professional Actors Training Program. He joined the Beta Theta Pi fraternity in college.
Very good friends with Tim Allen.