Leroy Jethro Gibbs is a fictional character

Fictional character

A character is the representation of a person in a narrative work of art . Derived from the ancient Greek word kharaktêr , the earliest use in English, in this sense, dates from the Restoration, although it became widely used after its appearance in Tom Jones in 1749. From this, the sense of...

 and the main protagonist

Protagonist

A protagonist is the main character of a literary, theatrical, cinematic, or musical narrative, around whom the events of the narrative's plot revolve and with whom the audience is intended to most identify...

 of the CBS

CBS

CBS Broadcasting Inc. is a major US commercial broadcasting television network, which started as a radio network. The name is derived from the initials of the network's former name, Columbia Broadcasting System. The network is sometimes referred to as the "Eye Network" in reference to the shape of...

 TV series NCIS

NCIS (TV series)

NCIS, formerly known as NCIS: Naval Criminal Investigative Service, is an American police procedural drama television series revolving around a fictional team of special agents from the Naval Criminal Investigative Service, which conducts criminal investigations involving the U.S...

. He is portrayed by Mark Harmon

Mark Harmon

Mark Harmon is an American actor who has been starring in American television programs and films since the mid-1970s, after a career as a collegiate football player with the UCLA Bruins. Since 2003, Harmon has starred as Leroy Jethro Gibbs in the CBS series NCIS.-Early life:Harmon was born Thomas...

.
Gibbs' age has never been revealed, but it was shown in the episode "Heartland" that he was born in rural Stillwater, Pennsylvania

Stillwater, Pennsylvania

Stillwater is a borough in Columbia County, Pennsylvania, United States. The population was 194 at the 2000 census. It is part of the Bloomsburg–Berwick Micropolitan Statistical Area.-Geography:Stillwater is located at ....

. His father, Jackson Gibbs (played by Ralph Waite

Ralph Waite

Ralph Waite is an American actor, whose most notable role was playing John Walton Sr. on the 1970s CBS TV series The Waltons, which he also occasionally directed...

), owns a store ("Stillwater General Store") in the same town. It has been mentioned in the episode "Frame Up" that Gibbs' father was possibly in the United States Army Air Force because Gibbs refers to a pin-up on his father's P-51 Mustang

P-51 Mustang

The North American Aviation P-51 Mustang was an American long-range, single-seat fighter and fighter-bomber used during World War II, the Korean War and in several other conflicts...

.