After 18 years of leading CBS’s most popular procedural drama, Mark Harmon is finally departing NCIS. The long-time lead, who first played the role in a backdoor pilot on JAG in 2003, exits the series after returning in a limited capacity for the series’ nineteenth season, finally giving up the mantle of supervisory special agent Leroy Jethro Gibbs.

Harmon made his departure during the fourth episode of Season 19 on Monday, during which Gibbs opted to remain in Alaska, where he had tracked down a hitman hired by a mining company. Having nearly been killed by an explosion during the finale of Season 18, the longtime special agent finally hung up his hat, refusing to return to his job in NCIS.

The Hollywood Reporter had previously noted that the series would likely have been canceled had Harmon not returned for Season 19, so it’s no surprise that this is the year Gibbs takes his final bow on the long-running crime drama.

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Image via CBS

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But, according to showrunner Steven D. Binder, this may not be the last we see of the character — particularly since Harmon still serves as executive producer on the series:

“As an executive producer and dear friend, Mark continues to be an integral part of the fabric of the show. Our north star has always been staying true to our characters, and that truth has always guided the stories we tell and where those characters go. So regarding the future of Gibbs, as long-time fans of the show may have noticed over the years … never count Leroy Jethro Gibbs out.”

Where the series will head after Harmon’s exit, no one can say for sure, though this isn’t the first time a long-running procedural has almost completely swapped out its original cast — just look at Law & Order: SVU. NCIS still retains some of its original and long-running cast members, however, including Sean Murray, Brian Dietzen, Rocky Carroll, and David McCallum, as well as series regulars Wilmer Valderrama and Diona Reasonover, who joined the series in its fourteenth season.

NCIS airs on CBS on Mondays at 9 p.m. ET.

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