Mark McCain is a fictional character from the television series The Rifleman, which aired from 1958 to 1963. He is portrayed by actor Johnny Crawford and is the son of the main character, Lucas McCain, played by Chuck Connors. Mark is depicted as a young boy growing up in the American West, learning valuable life lessons alongside his father. Throughout the series, Mark often finds himself in various adventures and challenges, showcasing his growth and development. The show highlights themes of family, morality, and the struggles of frontier life, with Mark serving as a central figure in many of the storylines.