Leroy Jethro Ebenezer Gibbs - a marine sniper turned NCIS agent with a broken and complicated background. He has been with the team since the very beginning. Depending on the character he is talking to he is either referenced as Gibbs, Boss, Probie or Jethro. He is the, sometimes enigmatic, leader of the team, who has a tendency to only communicate in grunts.

We first met him in Ice Queen & Meltdown, the back-door pilot which aired almost two decades ago. No one knew much about him back then. He had a talent when it came to talking with children, and he was fair and square while conducting the investigation against Harmon Rabb Jr.

A year later we re-met him while investigating the death of a security guard on the President's plane. He prefers to use old school methods, tricks and his gut when solving cases. He has a set of rules for everything. His team is led by the same principles he is trying to adapt to his personal life.

For several seasons we do not know much about his personal life: he has been married, divorced, and prefers red heads.

With the arrival of Jenny Shepard in s3 we start to learn things about him. He served in the Gulf War, his first wife - Shannon - and daughter - Kelly - were killed while he was away fulfilling his duties as a soldier. He almost died at the war, had an amnesia for a short while, and once he learnt about the murder of his family all he wanted was revenge on the man - Pedro Hernandez - who killed them.

This is why he joined NCIS, why he became the best at what he does. This is why he tries his best to ensure the safety of his team. He doesn't want them to go through the same guilt and grief he had to overcome. He hates lawyers and psychologists equally. For him ship-building is therapeutic - each one of his boats is named Kelly; after his long-dead daughter.

Throughout the seasons we meet each one of his wives, his former mother-in-law, the childhood best friend of his daughter, and the townspeople of Still water, where he came from. He has several flashback episodes - dealing with his past -, and Life before his eyes (9x10) features a myriad of what-ifs.

He has two best friends: T.J. Fornell - former FBI agent, and the ex-husband of his 2nd wife, Diane - and Phil, a marine turned accountant who faked his own death. He is also the godfather of Emily Fornell, the love child of Fornell and Diane. Whenever there is something wrong with the Fornell family he is the first person to be contacted. For Emily he's simply "Uncle Gibbs": the calmest person within her nuclear family. The unexpected murder of Diane was a shock for all of them, it became another death for which Gibbs could feel quilty about.

"The toughest guy I've ever met. I guess it's safe to say that no one had a tougher life than Agent Gibbs."
(Palmer - s14)

"We have suffered more broken hearts than most, Gibbs, enough to make us afraid to open them again."
(Ziva - s17)

Gibbs has healed a lot emotionally over the years, he has regular appointments with Grace - a psychologist recommended to him back in s13. Still he constantly battles with the guilt of killing Pedro Hernandez and his family, with "allowing" Kate, Jenny, Dorniget and Diane to get killed. He has a tendency to see ghosts whenever he is feeling guilty over a bad event. He either sees Mike, who was like a father to him, or Kelly, his young daughter, or even Diane. He loves his team as his own family, for him they are not just co-workers, but his children as well. He tried dating few times over the years with little luck. His longest relationships were with "Jamie Lee Curtis" and "Susanna Thompson".