Mark was born in Bell, California. He attended high school in the Inland Empire of that state where he met, and following a tour of duty in WW II, married Frances Mae Ferrell, his high school sweetheart. Nine months later they had a daughter named Teddy, who currently resides in 29 Palms, California. He returned to the Marine Corps for a tour of duty in Korea. Shortly after his return the family moved to Eugene, Oregon where Mark attended the University of Oregon as a journalism major. Being a superior trumpet player and possessing a velvety baritone voice, the stage was the natural place for him to end up. After graduation, he returned to California, in 1957, to seek a career in films and television. Frances died in 1969 and Mark married Sibyl Line and they were together till his death in 1993. Besides being a fine actor, who was admired by everyone he worked with, Mark supported the youth of his community. He was a Master Mason, and served for many years as a DeMolay dad. As his daughter was growing up, he was very active with Rainbow Girls and Girl Scouts. He was an avid horseback rider, which came in handy for all the westerns he made. As he grew older, he traded in his horse for a set of golf clubs.