The Definitive Answer: When Did Gibbs Leave NCIS? (Plus, His Shocking 2025 Return Confirmed)

The question of "When did Gibbs leave NCIS?" has been one of the most persistent in television history, and as of today, December 15, 2025, the answer is both a look back at a legendary exit and an exciting look forward at a confirmed return. The iconic Supervisory Special Agent Leroy Jethro Gibbs, played by Mark Harmon, officially retired from the Naval Criminal Investigative Service (NCIS) in 2021, marking the end of an era that spanned nearly two decades.

The definitive episode of his departure was a deeply emotional moment for fans, but the story didn't end there. Recent, major news has confirmed that Harmon is not only still involved with the franchise but is slated for an on-screen return in 2025, making the entire "Gibbs' status" conversation fresh and highly relevant again. This is everything you need to know about his exit, the reasons, and his shocking comeback.

Leroy Jethro Gibbs: Actor Mark Harmon's Full Profile

Before diving into the specifics of his *NCIS* departure and return, here is a quick look at the man behind the legendary character, Mark Harmon.

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• Full Name: Thomas Mark Harmon
• Date of Birth: September 2, 1951
• Place of Birth: Burbank, California, U.S.
• Age (as of 2025): 74
• Spouse: Pam Dawber (married 1987)
• Children: Sean Harmon, Ty Christian Harmon
• Notable Roles Before NCIS: Dr. Robert Caldwell on *St. Elsewhere*, Agent Simon Donovan on *The West Wing*, and various film roles like *The Presidio* and *Summer School*.
• NCIS Role: Supervisory Special Agent Leroy Jethro Gibbs (2003–2021)
• Franchise Role Post-Departure: Executive Producer for *NCIS: Origins* and confirmed on-screen return in 2025.
• Awards: Nominated for multiple Golden Globe and Emmy Awards throughout his career.

The Definitive Episode: When Gibbs Said Goodbye to NCIS

The moment that shook the *NCIS* universe happened early in the show's nineteenth season.

Season 19, Episode 4: "Great Wide Open"

Leroy Jethro Gibbs made his final appearance as a series regular in Season 19, Episode 4, titled "Great Wide Open." This episode first aired on October 11, 2021.

The lead-up to his departure was a winding road. Gibbs had been suspended indefinitely from NCIS earlier in the series after assaulting a suspect, a storyline that allowed for a reduced role for the actor.

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His final case brought him and Agent Timothy McGee (Sean Murray) to Alaska to investigate a contract killer hired by a powerful mining corporation.

The On-Screen Reason for His Departure

The ending of "Great Wide Open" was a quiet, emotional scene that solidified Gibbs' choice to leave his old life behind.

After solving the case, Gibbs tells McGee he has decided to remain in Naktok Bay, Alaska.

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He explains that he finally feels a sense of peace that he hasn't experienced since the deaths of his first wife, Shannon, and his daughter, Kelly, decades earlier.

The final, poignant line from Gibbs to McGee, as he stands by the river, was: "I’m not going back, Tim." He then tells McGee he feels "a great wide open," confirming his retirement from the stress and trauma of NCIS.

This exit left the door open for a potential return, as the character was alive and simply choosing a new life, rather than being killed off.

Why Mark Harmon Left NCIS: The Real-World Reason

While the on-screen reason for Gibbs’ departure was a search for peace in Alaska, the real-world reason behind Mark Harmon’s exit was a combination of fatigue and a desire for a reduced workload after nearly two decades on the show.

• A Desire to Work Less: After 18 full seasons as the lead, Harmon was reportedly ready to move on and wanted to work less. He negotiated a limited role for the beginning of Season 19, which allowed the show to transition his character out gracefully.
• A Complete Story Arc: Both Harmon and the show's creators felt that the character of Leroy Jethro Gibbs had reached a natural conclusion in his story. The suspension storyline and the search for a new purpose provided a fitting end for a character defined by his work and past trauma.
• Continued Involvement: Crucially, Harmon did not completely leave the *NCIS* universe. He remains an executive producer on the franchise, a role he leveraged to help develop the new prequel series.

His decision was not abrupt but a carefully managed transition that allowed the show to continue successfully with new leadership, including Gary Cole as the new Supervisory Special Agent Alden Parker.

The Shocking Update: Gibbs' Confirmed 2025 On-Screen Return

The biggest and most current news, as of late 2025, is that Mark Harmon is officially returning to the *NCIS* universe on-screen, marking his first return since his 2021 departure.

The NCIS: Origins Crossover Event

Harmon is set to reprise his role as Leroy Jethro Gibbs in a special, highly-anticipated crossover event between the flagship show, *NCIS*, and the upcoming prequel series, *NCIS: Origins*.

• Confirmed Air Date: The crossover episode is currently slated to air on Tuesday, November 11, 2025.
• The Role: While Harmon is the narrator and executive producer of *NCIS: Origins*, which focuses on a young Gibbs, this crossover confirms his on-screen return as the older, present-day Gibbs.
• A New Look: Early teasers and trailers for the 2025 crossover have shown a new, "unrecognizable" look for Gibbs, suggesting a significant time jump or a new phase in his life following his retirement in Alaska.

This news has reignited fan excitement and speculation, as it confirms that the character is still a vital part of the franchise's future, even if he is no longer in the bullpen every week. His on-screen return in 2025 will be a major television event, providing new closure or perhaps a new mystery for the beloved character.

The Enduring Legacy of Agent Gibbs

Gibbs’ departure from *NCIS* in Season 19, Episode 4, "Great Wide Open," was a necessary and earned rest for a character who had endured immense tragedy and stress over 18 seasons.

The character's legacy—defined by his strict rules, his boat-building in the basement, and his unwavering loyalty to his team—continues to influence the show.

The decision by Mark Harmon to step back, but remain involved as a producer and now with a confirmed on-screen return in 2025, ensures that the spirit of Leroy Jethro Gibbs will continue to shape the *NCIS* universe for years to come. Fans who missed the stoic agent can now look forward to his brief, but meaningful, return to the screen.