The Definitive Answer: When Did Gibbs Leave NCIS—And The Shocking Crossover Return Set For 2025

The question of "When did Gibbs leave NCIS?" is one of the most searched queries in television history, marking the end of an era for the long-running procedural drama. As of today, December 18, 2025, the definitive answer is that Special Agent Leroy Jethro Gibbs officially retired from the Naval Criminal Investigative Service during the airing of Season 19, but the door was purposefully left open for the beloved character. His departure was not a dramatic death or a forced exit, but a peaceful, earned retirement that allowed both the character and actor Mark Harmon to find new purpose.

The exact moment Gibbs stepped away from the team occurred in the fourth episode of Season 19, titled "Great Wide Open," which premiered in October 2021. This monumental episode saw Gibbs decide to remain in Naktok, Alaska, after successfully solving a complex case alongside Agent Timothy McGee. However, for fans still holding out hope, the latest, most crucial update is the confirmed news of Mark Harmon's return as Gibbs in a major cross-series event scheduled for November 2025, tying the original show to the new prequel, *NCIS: Origins*.

Mark Harmon: A Comprehensive Biography and Career Profile

To fully appreciate the impact of Leroy Jethro Gibbs’ departure, one must first understand the man who brought him to life for nearly two decades. Thomas Mark Harmon, born on September 2, 1951, in Burbank, California, is a figure whose career spans professional sports, film, and, most notably, a legendary run in television.

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Harmon’s lineage is steeped in American culture. He is the son of football legend and Heisman Trophy winner Tom Harmon and actress Elyse Knox. Following in his father’s athletic footsteps, Mark Harmon was a highly recruited college football player, serving as the starting quarterback for the UCLA Bruins in the early 1970s.

His transition to acting saw him quickly rise to prominence. He became a familiar face on television, establishing his career with a four-year run as Dr. Robert Caldwell on the critically acclaimed drama *St. Elsewhere* in the 1980s. Other significant roles included a period on *Chicago Hope* and a notable turn as Secret Service Agent Simon Donovan on *The West Wing*.

However, it was his casting as the stoic, rule-bending, and deeply moral Special Agent Leroy Jethro Gibbs in 2003 that cemented his legacy. Harmon spent 19 seasons as the face of the *NCIS* franchise, not only starring but also serving as an executive producer, guiding the show to become one of the most-watched dramas globally.

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• Full Name: Thomas Mark Harmon
• Born: September 2, 1951 (Burbank, California, USA)
• Parents: Tom Harmon (Heisman Trophy Winner) and Elyse Knox (Actress)
• Education: University of California, Los Angeles (UCLA)
• Spouse: Pam Dawber (m. 1987)
• Notable Roles: Dr. Robert Caldwell (*St. Elsewhere*), Agent Simon Donovan (*The West Wing*), Leroy Jethro Gibbs (*NCIS*)
• NCIS Tenure: 2003–2021 (19 Seasons)

The Definitive Exit: Gibbs Finds Peace in Alaska

The slow-burn storyline that led to Gibbs’ eventual departure began well before the official exit episode. The groundwork was laid in Season 18 when Gibbs was suspended indefinitely from NCIS after assaulting a man who was abusing dogs. This suspension storyline allowed the character to operate outside the official NCIS structure, exploring new avenues and setting the stage for his retirement.

The final, definitive moment came in Season 19, Episode 4, "Great Wide Open." The episode focused on Gibbs and McGee traveling to Naktok, Alaska, to investigate a case involving a hired killer. During their time in the remote location, Gibbs finally solved the case that had haunted him for months.

The true climax of the episode was not the case, but the emotional conversation between Gibbs and McGee while fishing. Gibbs, known for his relentless work ethic and inability to sit still, expressed a profound sense of peace he hadn't felt since the tragic deaths of his first wife, Shannon, and daughter, Kelly.

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His final words to McGee, "I’m not going back," confirmed his decision to leave NCIS for good and remain in Alaska. This was a highly unusual, yet fitting, send-off for a character who had spent nearly two decades dealing with trauma and loss. The exit was a quiet, earned retirement, leaving the door open for future appearances rather than closing it with a dramatic death.

The actor's decision to leave was driven by a desire to step back from the grueling schedule of a lead role in a major network drama. Mark Harmon, who had been the series' anchor for 19 years, negotiated a limited appearance in Season 19 before ultimately deciding to exit. He stated that he felt the character’s story had reached a natural and complete conclusion.

The Future of Gibbs: Executive Producer Role and Confirmed 2025 Return

While Leroy Jethro Gibbs is no longer a mainstay on the main *NCIS* team, Mark Harmon’s involvement with the franchise is far from over. In fact, his role has evolved, giving him a powerful new position within the *NCIS* universe.

Harmon transitioned from lead actor to executive producer and narrator of the new prequel series, *NCIS: Origins*. This spin-off, which is set in 1991, explores the early career of a young Leroy Jethro Gibbs as a probationary NIS Agent at the Camp Pendleton office, still processing the trauma of his family's deaths.

The prequel series is a major focus for the franchise, and it has provided the perfect vehicle for Mark Harmon to remain connected to the character he defined. His son, Sean Harmon, who has played a younger version of Gibbs in flashbacks on the main show, is also involved in the new series, further cementing the family's legacy within the *NCIS* world.

The Shocking 2025 Crossover Event

The most exciting news for fans is the confirmed return of Mark Harmon as the present-day Leroy Jethro Gibbs. CBS has scheduled a major *NCIS* and *NCIS: Origins* crossover event for November 11, 2025, coinciding with Veteran’s Day.

This event will link the current-day NCIS investigation with a case from young Gibbs’ past, providing a massive, high-stakes narrative that spans decades. While the exact details of how Gibbs will be reintroduced are being kept under wraps, the confirmation that Harmon will physically reprise the role is a monumental moment for the franchise.

This return is a testament to the showrunners' commitment to keeping Gibbs' story alive and honoring the character's legacy. It also demonstrates that the peaceful Alaskan retirement was a narrative choice designed to allow for these special, meaningful appearances, rather than a final goodbye. The possibility of future guest spots, even after the 2025 crossover, remains high, ensuring that while Gibbs may have left the team, he has not truly left the *NCIS* family.

Topical Authority: Gibbs’ Presence in NCIS Season 22

Even in his absence, Leroy Jethro Gibbs remains a powerful, guiding force in the main *NCIS* series. The character's spirit and rules are often referenced by the current team, including Director Leon Vance and Agent Timothy McGee.

In a beautiful nod to the former lead, *NCIS* Season 22, Episode 19, symbolically reintroduced Gibbs. While he didn't physically appear, the episode utilized emotional resonance and storytelling to make his presence felt, proving that his influence on the team and the show’s moral compass is permanent. This continuous topical thread ensures that the question of "When does Gibbs return?" remains as relevant as "When did Gibbs leave?"

The legacy of Gibbs is now split between his peaceful retirement in Alaska, his mentorship of the current team, and the exploration of his foundational years in *NCIS: Origins*. The upcoming 2025 crossover is the ultimate payoff for patient fans, finally bringing the legendary agent back to the screen after his definitive Season 19 exit.

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Key Entities and LSI Keywords:

• Leroy Jethro Gibbs
• Mark Harmon
• NCIS Season 19, Episode 4
• "Great Wide Open"
• Naktok, Alaska
• NCIS: Origins
• NCIS Crossover 2025
• Timothy McGee
• CBS Drama
• Executive Producer
• Probationary NIS Agent
• St. Elsewhere
• Tom Harmon
• Shannon and Kelly Gibbs
• Gary Cole (Agent Parker)