Summary
The real reason why Leroy Jethro Gibbs doesn’t lock his front door is revealed by a formerNCISactor. For almost two decades, Mark Harmon’s character was the fearless leader of DC’s Major Case Response Team (MCRT). Aside from his leadership style, which was rooted in loyalty and fairness,NCISalso added certain quirks to the character, including his penchant for leaving his front door open. This means that anyone could come in, which seemed like a dangerous habit for a law enforcer.Gibbs left in NCIS season 19, leaving the reason for the oddity unexplained.
Almost three years since Harmon walked away from the police procedural, this mystery is finally clarified in a new episode ofOff Duty: An NCIS Rewatchpodcast. As part of the Spotify show’s trivia segment, Ziva David first asks her co-host, Michael Weatherly, and guest of the week, Sean Murray, about the matter, but they couldn’t answer. In the end, she reveals the official reason beingtied to Gibbs' heartbreaking past of losing his family. Read the full answer below:

The answer is because he has already lost what was most important to him, so he actually doesn’t care.
How NCIS: Origins Can Make Gibbs’ Front Door Trait Sadder
NCIS: Origins Take Place Around The Time Of Kelly & Shannon’s Murder
After a short break from the franchise, Harmon is set to return via Gibbs' prequel series titledNCIS: Origins. Per the upcoming show’s premise, theNCISspinoff will take place in the early ’90s, as he begins his storied career with the agency. Instead of being in Washington DC, however, the project will beset in Camp Pendleton, with the young Gibbs joining the rag-tag team that Mike Franks is leading. Assuming that it will stay true to the establishedNCIStimeline, then it’s also around the time whenhis first wife, Shannon, and daughter, Kelly, were murdered.
WhetherNCIS: Originswill showAustin Stowell’s recast version of young Gibbsgoing through the agony of finding out about what happened to his family is uncertain. However, considering how he never got over their deaths, seeing him processing the fresh loss would make his front door quirk more heartbreaking. It’s curious, however, when exactly he adopted this behavior, especially since he would be based on the West Coast during the duration ofNCIS: Origins. It’s one of the many questions that can be answered in the prequel that can show Gibbs in a different light.
Admittedly, there are concerns aboutNCIS: Originstackling Gibbs' backstory will dull the character’s appeal by revealing too much about him. This means that CBS and the writers must be careful not to overdo it, especially when it comes to tackling certain aspects of Gibbs' life that are better left not fully fleshed out. IfNCISproves anything, he is best when there’s an air of mystery around him.
NCIS
Cast
NCIS is a television series that follows a team of special agents from the Naval Criminal Investigative Service. Premiering in 2003, the show explores various cases involving Navy and Marine Corps personnel, ranging from murder and espionage to terrorism and stolen submarines.