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.
Was not the original actor chosen to be Al on Home Improvement (1991). Stephen Tobolowsky was originally cast and Richard filled in as a favor to the directors of the pilot, when Stephen wasn't available. Once Stephen decided to pursue a movie career, Richard agreed to stay on as Al.
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.
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.
In June 2020, he announced that he would no longer be honoring requests for autographs.