Meet Mark Harmon’s 2 Sons, Sean and Ty

The longtime couple, who married in 1987, have kept their family life private over the years. In November 2023, Harmon told PEOPLE that his commitment to raising his children influenced his decision to take on his now-iconic role as Leroy Jethro Gibbs on NCIS. “I was trying to stay home more with a young family,” he said.

While Sean and Ty, both of whom are now adults, keep a relatively low profile, they followed their parents into show business — Ty tried his hand at screenwriting, and Sean is a stuntman and actor. The latter has appeared on both NCIS and the spinoff NCIS: Origins. He played FBI agent Casey Bloom in one episode of Origins and also serves as an executive producer.

“I’m proud of both our boys, and they work hard at what they do and I’m proud that they get up in the morning and try to do that every day,” Harmon told Entertainment Tonight in November 2020.

Here’s everything to know about Mark Harmon’s children, sons Sean and Ty.

Sean Harmon, 38

Mark and Dawber welcomed their first child, Sean, on April 25, 1988, in Burbank, Calif., one year after they married.

He spent his childhood away from the spotlight and pursued a career in show business as an adult.

One of Sean’s first forays into acting came when he appeared on NCIS as a younger version of his dad’s character, Leroy.

He stepped into the role during season 6 of the CBS procedural drama. Sean appeared in eight total episodes of the show, and in October 2026, he joined his dad again for NCIS: Origins, in which he played Casey, an FBI agent.

Sean is also a stunt performer and coordinator who specializes in fight scenes. His work has been featured in TV shows like Breakwater and films like Dumb and Dumber To.

Off-screen, Sean is married to producer Courtney Prather Harmon. The pair tied the knot in November 2022 and welcomed their son, Cooper, in May 2025, making Harmon and Dawber first-time grandparents.

Harmon and Dawber welcomed their second son, Ty, on June 25, 1992.

Ty also pursued a career in Hollywood, albeit behind the camera. He is a screenwriter and worked with his brother on a short film called Catholic Schoolgirl Chainsaw Showdown in 2012.

Ty works in visual effects, and has credits on movies like The Marvels and TV shows like Grip and For All Mankind.

Like his brother, Ty is also married. He wed Madeline Harmon in February 2021 and the couple share two dogs, per his Instagram.