Harmon was born in Burbank, California, the youngest of three children. His parents were Heisman Trophy-winning football player and broadcaster Tom Harmon and actress, model, and artist Elyse Knox (née Elsie Lillian Kornbrath).
Harmon had two older sisters, the late actress and painter Kristin Nelson, who was divorced from the late singer Rick Nelson, and actress and model Kelly Harmon, formerly married to car magnate John DeLorean. His maternal grandparents were Austrian immigrants.
College football
After his high school graduation from Harvard-Westlake School in 1970, Harmon completed a two-year associate degree at Pierce College in Los Angeles. After his second season at Pierce, 1971, Harmon received offers from major college football programs, ultimately choosing UCLA over Oklahoma, even though in the previous season, 1971, the Sooners finished second in the nation, while the Bruins had stumbled to a 2–7–1 record, placing last in the Pac-8.
After transferring to the University of California, Los Angeles, he started as quarterback for the 1972 and 1973 Bruins.
During his first game, his UCLA team produced a stunning upset of the two-time defending national champion Nebraska Cornhuskers. The Bruins were an eighteen-point home underdog to the top-ranked Huskers but won 20–17 on a late field goal by Efren Herrera at L.A. Coliseum.
In his senior year, Harmon received the National Football Foundation Award for All-Round Excellence. During his two years as quarterback in coach Pepper Rodgers's wishbone offense, UCLA compiled a 17–5 record. Harmon was UCLA's starting quarterback for two seasons, but he was not picked in the 1974 NFL draft.
Harmon graduated cum laude from UCLA in 1974 with a B.A. in Communications.
He was inducted into the inaugural class of the Pierce College Athletic Hall of Fame in 2010.
Career
After college, Harmon considered pursuing a career in advertising or law. Harmon started his career in business as a merchandising director, but soon decided to switch to acting. He spent much of his career portraying law enforcement and medical personnel. One of his first national TV appearances (other than as an athlete) was in a commercial for Kellogg's Product 19 cereal with his father, Tom Harmon, its longstanding TV spokesman. Thanks to his sister Kristin's in-laws, Ozzie Nelson and Harriet Nelson, he landed his first job as an actor in an episode of Ozzie's Girls. This was followed by guest roles in episodes of Adam-12, Police Woman, and Emergency! in mid-1975. He also performed in "905-Wild", a backdoor pilot episode for a series about two L.A. County Animal Control Officers which did not sell. Producer/creator Jack Webb, who was the packager of both series, later cast Harmon in Sam, a short-lived 1978 series about an LAPD officer and his K-9 partner. Before this, Harmon received an Emmy nomination for Outstanding Supporting Actor in a Miniseries or a Movie for his performance as Robert Dunlap in the TV movie Eleanor and Franklin: The White House Years. In 1978, he appeared in three episodes of the mini-series, Centennial, as Captain John MacIntosh, an honorable Union cavalry officer.
Personal life
Harmon is the son of football player Tom Harmon and actress Elyse Knox. His sisters are Kelly, an actress and model, and Kristin, an actress and painter. Kristin died of a heart attack on April 27, 2018.
Harmon has been married to actress Pam Dawber since March 21, 1987. The couple has two sons. His son Sean played a young Gibbs in several NCIS episodes. They maintain a low profile and rarely appear in public with their children. Harmon was the brother-in-law of Ricky Nelson and John DeLorean and is the uncle of actress Tracy Nelson and singers Matthew and Gunnar Nelson of the rock duo Nelson.
In 1987, Harmon filed for custody of his nephew Sam, Kristin's son, on the grounds that she was incapable of good parenting. Sam's psychiatrist testified that the thirteen-year-old boy depicted his mother as a dragon and complained about her mood swings and how she prevented him from being with his siblings. Harmon later dropped the custody bid.
In 1988, Harmon was part owner of a minor league baseball team, the San Bernardino Spirit, the same season Ken Griffey Jr. played for the team before his major league call-up to the Seattle Mariners the next season. Harmon used the team and their home field, Fiscalini Field, for the opening and closing scenes of the film in which he was starring, Stealing Home.
In 1996, Harmon saved a teenage boy involved in a car accident outside his Brentwood home. The driver had been able to escape, but the passenger was trapped in the burning car. Dawber telephoned emergency services, while Harmon used a sledgehammer from his garage to break the window of the car and pulled the passenger from the vehicle. The passenger suffered severe burns but survived his injuries.
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