Leroy Jethro Gibbs is the special agent in charge on NCIS.

Gibbs joined the United States Marine Corps instead of attending college. He became a Scout Sniper.

In his free time, he is occasionally shown in his basement building a boat, which he named after his daughter.

Gibbs' age has never been revealed, but it was shown that he was born in rural Stillwater, Pennsylvania. His father, Jackson Gibbs, owns a store (the 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.

He is named after his father's friend, Leroy Jethro, who was his business partner in the store after having worked together in the coal mines. The younger Gibbs left Stillwater in 1976 at the approximate age of 18-20 and, according to his own statements, did not return for over 30 years.

At NCIS, Gibbs is portrayed as a consummate organizer, disciplined and demanding. These traits often put him in a stand-off with other authorities when pressure is being asserted at his team.

He remains a Marine reservist.

Before the time in which NCIS is set, Gibbs travelled extensively on operations, particularly in Eastern Europe, demonstrated by many flashbacks, many including Director Jenny Shepard.

Gibbs displays a continuous urgency about the investigation he pursues, specifically when being given technical information about, complex subject matter.

The typical response to such information is "Give it to me in English", thus forcing the expert to get to the point, as well as making it easy on the audience.

Gibbs has been married three times and had one daughter named Kelly.

Leroy Jethro Gibbs Quotes

Keates: Spider?
Tony: Keates?
Gibbs: You know her?
Tony: Um, well I..in a sort of...yeah. She's Philly PD.
Keates: She was. She's ATF now. Special Agent Zoe Keates. You want to get that gun out of my face and come over here and give me a hug?

There is no such thing as coincidence. (Season 7, Episode 21)

Rule #39

NCIS Quotes

‘You think you’re alone in the dark. Close your eyes. Remember everything good.’ My mom said that to me just before she died. Smart lady.

Gibbs

Morrow: There's a connection between the death of that Navy Seal and what's happening with your team.
Vance: What kind of connection?
Morrow: The murder of Eli David opened a political can of worms that was much bigger than anyone expected.
Vance: Eli and Arash Kazmi wanted to forget a peace. But Bodnar killing them opened the door.
Morrow: Homeland and the CIA wait for chances like this, to stir the pot. Distract governments so that all sorts of recon can happen. The CIA needed Iran to believe Mossad was responsible.
Vance: Are you telling me that Bodnar didn't kill Kazmi?
Morrow: I'm telling you we did it, Leon. The CIA took out Kazmi that night so that Bodnar would end up being the fall guy. Iran and Israel could duke it out while we focused on the real threat. We're all so damned worried about Iran and North Korea when the real threat is here, on home soil.
Vance: It's a shell game isn't it? Keep people distracted.
Morrow: Leon you see why I wanted you to keep your distance?