Step 1 : Introduction to the question "Who is the only actor to appear in both the “M*A*S*H” movie and TV show?"
Gary Burghoff is the only actor to appear in both the "MAS*H" movie and TV show. In the 1970 film directed by Robert Altman, Burghoff portrayed Corporal Walter "Radar" O'Reilly, a character celebrated for his exceptional hearing and charming naivety. When the film was adapted into a television series, Burghoff was the only cast member to reprise his role. In the film, other notable cast members included Donald Sutherland as Hawkeye, Elliott Gould as "Trapper" John McIntyre, Sally Kellerman as Margaret "Hot Lips" Houlihan, and Robert Duvall as Frank Burns.