Donald Losby, born Donald A. Losby, Jr., on May 26, 1951, in San Francisco, California, is an American actor, known primarily for his many character roles in popular television during the 1950s and 1960s in programs such as The Adventures of Ozzie and Harriet, The Andy Griffith Show, The Twilight Zone, Bonanza, Rawhide, Route 66, The Fugitive, Ben Casey, Lassie, My Three Sons, Gunsmoke, Daniel Boone,Blue Light, Lost in Space, and The Young Rebels, as well as a small number of movies, typically playing the role of someone's son.