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

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

Appearances as themselves (20)

• 2024NCISverse: The First 1,000 — Self
• Joe Montana: Cool Under Pressure — Self - Narrator (voice)
• The Kelly Clarkson Show — Self
• 2019The Wild — Self
• The American West — Self
• The Late Late Show with James Corden — Self
• The Late Show with Stephen Colbert — Self - Guest
• The Arsenio Hall Show — Self
• Steve Harvey — Self
• The Bonnie Hunt Show — Self
• The Megan Mullally Show — Self - Guest
• The Tony Danza Show — Self
• Jimmy Kimmel Live! — Self
• 2002Intimate Portrait: Pam Dawber — Self
• The View — Self
• The Rosie O'Donnell Show — Self
• Entertainment Tonight — Self
• Saturday Night Live — Self - Host
• The Tonight Show Starring Johnny Carson — Self
• Golden Globe Awards — Self - Nominee