Raised in North Hollywood, California, his father was Aldrich "Kit" Carson (Kit Carson), an actor who appeared in many westerns, most notably working with Dale Robertson. His mother, Rosamonde "Boots" James Carson, also had acting experience, but was primarily a fashion model, and elected president of the Mannequins Association of Los Angeles in 1968. Johnny started his career doing commercials, including one at age 5 or 6 portraying a circus ringmaster for a local department store. He later did cartoon voices for Hanna-Barbara. While attending Valley College, he played a lead role in "Taming of the Shrew" staged by the drama department in November, 1969. After his debut in feature films, there was a dispute with Johnny Carson of The Tonight Show regarding use of the name John Carson. At that time, he began to use the name John David Carson. He was romantically linked with Kim Darby at the time of her ex-husband's, Jim Stacy, motorcycle accident when he lost an arm and a leg. They met while she was filming os segment of "Love Story", which aired on NBC on December 12 of that year.