His Sister Kelly
In addition to having parents in show business, Mark Harmon’s sisters also appeared on the big screen. His sister Kelly Harmon is best known for appearing in shows Bay City Blues, Battlestar Galactica, CHiPS, and One Day At A Time. She later began a career in interior design and even owns her own company that is located in Los Angeles.
His Sister Kristin
Mark’s sister Kristin also briefly spent some time as an actress and model, and was also married to actor and musician Ricky Nelson. The two had four children, but later went through a very bitter divorce. She then married Mark Tinker, who encouraged her desire to paint. Her paintings became very sought after, with Jackie Kennedy and Mia Farrow purchasing her works.