
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.
Gallery




Known For
Acting History
2025
Freakier Friday as Ryan
2024NCIS: Origins as Older Leroy Jethro Gibbs (voice) (uncredited)
2024NCIS: Origins as Older Leroy Jethro Gibbs (uncredited)
2024NCISverse: The First 1,000 as Self
2022Joe Montana: Cool Under Pressure as Self - Narrator (voice)
2019The Kelly Clarkson Show as Self
2019The Wild as Self
2018All or Nothing: The Michigan Wolverines as Narrator (voice)
2016The American West as Self
2015The Late Late Show with James Corden as Self
2014NCIS: New Orleans as Leroy Jethro Gibbs
2013The Arsenio Hall Show as Self
2011Certain Prey as Lucas Davenport
2010Justice League: Crisis on Two Earths as Superman (voice)
2009Weather Girl as Dale
2008The Bonnie Hunt Show as Self
2006The Megan Mullally Show as Self - Guest
2004The Tony Danza Show as Self
2004Chasing Liberty as James Foster
2003NCIS as Leroy Jethro Gibbs
2003Freaky Friday as Ryan
2003Jimmy Kimmel Live! as Self
2002Local Boys as Jim Wesley
2002Intimate Portrait: Pam Dawber as Self
2001The Legend of Tarzan as Bob Markham (voice)
2001And Never Let Her Go as Thomas Capano
2001And Never Let Her Go as Thomas Capano
2001Crossfire Trail as Bruce Barkow
2001The Amati Girls as Lawrence
2000For All Time as Charles Lattimer
1999The West Wing as Simon Donovan
1999I'll Remember April as John Cooper
1999Family Guy as Leroy Jethro Gibbs (voice)
1998Fear and Loathing in Las Vegas as Magazine Reporter
1998From the Earth to the Moon as Wally Schirra
1997The View as Self
1997Casualties as Tommy Nance
1997The First to Go as Jeremy Hampton
1996The Rosie O'Donnell Show as Self
1995JAG as Leroy Jethro Gibbs
1995Charlie Grace as Charlie Grace
1995The Last Supper as Dominant Male
1995Magic in the Water as Jack Black
1995Original Sins as Johnathan Franye
1994Chicago Hope as Jack McNeil
1994Natural Born Killers as Mickey Knox in TV
1994Wyatt Earp as Sheriff Johnny Behan
1993Harts of the West
1992Cold Heaven as Alex Davenport
1992The Tonight Show with Jay Leno
1991Reasonable Doubts as Det. Dicky Cobb
1991Till There Was You as Frank Flynn
1991Shadow of a Doubt as Charles Spencer
1991Long Road Home as Ertie Robertson
1991Fourth Story as David Shepard
1991Dillinger as John Dillinger
1989Worth Winning as Taylor Worth
1989Sweet Bird of Youth as Chance Wayne
1988Stealing Home as Billy Wyatt
1988The Presidio as Jay Austin
1987After the Promise as Elmer Jackson
1987Dear America: Letters Home from Vietnam as (voice)
1987Summer School as Mr. Freddy Shoop
1986Let's Get Harry as Harry
1986The Deliberate Stranger as Ted Bundy
1986The Deliberate Stranger as Ted Bundy
1986Prince of Bel Air as Robin Prince
1985Moonlighting as Sam Crawford
1984Tuareg: Desert Warrior as Gacel Sayah
1983Intimate Agony as Tommy
1982St. Elsewhere as Robert Caldwell
1981Goliath Awaits as Peter Cabot
1981Entertainment Tonight as Self
1981Flamingo Road as Field Carlyle
1980The Dream Merchants as Johnny Edge
1980Flamingo Road as Fielding Carlyle
1979240-Robert as Thib Thibideaux
1979Beyond the Poseidon Adventure as Larry Simpson
1978Comes a Horseman as Billy Joe Meynert
1978Centennial as Captain John McIntosh
1978Little Mo as Norman Brinker
1978Getting Married as Howie Lesser
1978Sam as Mike Breen
1977The Love Boat as Doug Bradbury
1977Eleanor and Franklin: The White House Years as Robert Dunlap
1977The Hardy Boys / Nancy Drew Mysteries
1976All's Fair
1976Delvecchio as Ronnie Striker
1976Laverne & Shirley
1975Saturday Night Live as Self - Host
1974Police Woman as Stanski
1974Police Woman as Paul Donin
1974Sonic Boom as Student Controller
1973Ozzie's Girls
1972Emergency! as Ofcr. Dave Gordon
1968Adam-12 as Officer Gus Corbin
1962The Tonight Show Starring Johnny Carson as Self
1951Hallmark Hall of Fame as Charles
1944Golden Globe Awards as Self - Nominee
1944Golden Globe Awards as Self









