
Mark Harmon
Biography
Thomas Mark Harmon (born September 2, 1951) is an American actor, producer and director. He is known for playing the lead role of Leroy Jethro Gibbs on NCIS (2003-2021), a role which has earned him six nominations at the People's Choice Awards including a win for Favorite TV Crime Drama Actor in 2017. Since 2008, he has also been a producer and executive producer of the show as well as its' spinoff series NCIS: New Orleans. His character of NCIS special agent Leroy Jethro Gibbs was introduced in a guest starring role in two episodes of JAG, and continued on the spinoff show NCIS.
He had a recurring role as Secret Service special agent Simon Donovan in a four-episode story arc in The West Wing in 2002, for which he received an Emmy Award nomination.
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 and Harriet Nelson, he landed his first job as an actor in an episode of Ozzie's Girls.
He has been starring in television and film since the mid-1970s, after a career as a collegiate football player with the UCLA Bruins.
He's been married to actress Pam Dawber since 1987 and they have 2 sons. His son, actor Sean Harmon, had a recurring role as a young Leeroy Jethro Gibbs on NCIS.
Filmography

Freakier Friday
2025
as Ryan

NCISverse: The First 1,000
2024
as Self

The Wild
2019
as Self

Certain Prey
2011
as Lucas Davenport

Justice League: Crisis on Two Earths
2010
as Superman (voice)

Weather Girl
2009
as Dale

Chasing Liberty
2004
as James Foster

Freaky Friday
2003
as Ryan

Local Boys
2002
as Jim Wesley
- No poster
Intimate Portrait: Pam Dawber
2002
as Self

And Never Let Her Go
2001
as Thomas Capano

Crossfire Trail
2001
as Bruce Barkow

The Amati Girls
2001
as Lawrence

For All Time
2000
as Charles Lattimer

I'll Remember April
1999
as John Cooper

Fear and Loathing in Las Vegas
1998
as Magazine Reporter

Casualties
1997
as Tommy Nance

The First to Go
1997
as Jeremy Hampton

The Last Supper
1995
as Dominant Male

Magic in the Water
1995
as Jack Black

Original Sins
1995
as Johnathan Franye

Natural Born Killers
1994
as Mickey Knox in TV

Wyatt Earp
1994
as Sheriff Johnny Behan

Cold Heaven
1992
as Alex Davenport