Why Did Mark Harmon Abruptly Leave NCIS?

After acting in television for nearly half a century, NCIS star Mark Harmon needed a break

When Mark Harmon began his historic run as Special Agent Leroy Jethro Gibbs on the CBS police procedural television series NCIS in 2003, he had been acting on television for approximately thirty years. However, despite the vast experience that Harmon brought to NCIS, nothing could have prepared Harmon for a run that lasted approximately eighteen years. Indeed, prior to NCIS, Harmon’s longest run on a television series had been on the CBS medical drama series Chicago Hope, in which Harmon appeared in ninety-five episodes over four seasons between 1996 and 2000. Harmon has currently appeared as Gibbs in 435 episodes of NCIS, which is presently the third longest-running live-action scripted prime-time television series in history.

Harmon made his last appearance on NCIS in the “Great Wide Open” episode, which first aired on October 11, 2021, as the fourth episode of the show’s 19th season. However, while this episode represents a touching goodbye for Harmon, Gibbs is still very much alive, while Harmon has declared that he’s not retired from acting. Moreover, as the various reasons for Harmon’s departure from NCIS have become increasingly clear over the past two years, there has been continuous speculation regarding the possibility of Harmon returning as Gibbs, if for no other reason than to say one final goodbye before the show, which is set to begin its twenty-first season in February 2024, finally reaches the end of its run.

It Was Time For Harmon to Walk Away From NCIS

The “Great Wide Open” episode of NCIS ends with Leroy Jethro Gibbs fishing in the quiet waters of Alaska with NCIS Special Agent Timothy McGee. When a water plane arrives, Gibbs tells a stunned McGee that he isn’t returning with McGee to D.C. but has instead decided to stay in Alaska, where he has found a sense of peace that he hasn’t felt since his daughter and first wife were murdered.It was no accident that Mark Harmon decided to make his final appearance as Gibbs early in the show’s 19th season, instead of at the end of the previous season. By appearing as Gibbs through the end of the show’s eighteenth season, Harmon, who has been credited as an executive producer on NCIS since 2008, understood that the show had a much better chance of being renewed for a nineteenth season if the central Gibbs character was still around, at least for four more episodes.

After approximately eighteen years, Harmon was ready to leave NCIS. He was tired. While Harmon had, prior to joining NCIS, certainly been accustomed to the rigorous demands of a television series production schedule with his previous featured roles on Chicago Hope and St. Elsewhere, both of which placed Harmon within an ensemble cast, whereas the fate of NCIS largely depended on Harmon’s presence. As the star of NCIS, there was no respite for Harmon, and it was simply time for a break.

A second reason that Mark Harmon has given for his decision to leave NCIS is that Harmon, after playing the role of Leroy Jethro Gibbs for 18 seasons, wants to play other roles. Indeed, throughout his run on NCIS, the only outside film and television projects that Harmon appeared in were the 2004 comedy film Chasing Liberty, which was filmed prior to the debut of NCIS, the 2009 comedy film Weather Girl, and the 2011 made-for-television film Certain Prey.

The paucity of outside film and television projects that Harmon was able to pursue throughout his run on NCIS reflects how much the television industry has changed since Harmon experienced his first wave of television fame in the 1980s with the NBC medical drama television series St. Elsewhere.

Whereas television stars of the 1980s, like Harmon, Don Johnson, and Tom Selleck were able to pursue other projects, specifically feature films, when their shows were on hiatus, this grace period doesn’t seem to exist anymore, seemingly because of the grueling production schedules for shows like NCIS. Regardless, more than two years after Harmon made his final appearance on NCIS, he still hasn’t appeared in any other film and television projects, nor is he presently attached to any upcoming film and television projects.

Much like the transforming effect that the police procedural drama television series Blue Bloods has had on the career and legacy of Tom Selleck, Mark Harmon’s performance as Leroy Jethro Gibbs on NCIS has redefined Harmon’s career and legacy and overwhelmed his past. Since Gibbs is virtually the only role that Harmon has played in the past twenty years, the character is the only point of reference that most people under the age of thirty have for Harmon. Moreover, given the seemingly omnipresent existence that reruns of NCIS have continued on television for more than a decade, this perception isn’t likely to change throughout the remainder of Harmon’s career and life.

Of course, many people are old enough to have followed Harmon’s career in the 1980s, from St. Elsewhere to Moonlighting to Harmon’s bid for feature film stardom with films like The Presidio and Summer School. For them, the current image of seventy-two-year-old Harmon is so far removed from Harmon’s sex-symbol persona from the 1980s that the older and younger incarnations of Harmon now seem like two entirely different people.

After a long career in television starring on some beloved shows, it would be understandable if Harmon decided to retire at this stage. However, the fact of his age also doesn’t guarantee that he won’t want to get back to work in the future. Michael Cain has threatened retirement a number of times but always seems to come back for one more performance. So, only time will tell if we’ll see the hard-working actor back on the screen any time soon.