If Mark Harmon's Gibbs ever does return to NCIS, here's how it might happen. Harmon has been a member of the NCIS family ever since it emerged as a JAG spinoff in 2003, playing the steely-eyed leader of the procedural's core team. As Leroy Jethro Gibbs, the actor anchored the series and stood at the center of some of its most emotional storylines. This explains why so many viewers were thrown off when just four episodes into NCIS season 19 Gibbs left the team to stay behind in Alaska, having achieved the kind of peace he had long been searching for after his wife and daughter's deaths.
Since his departure, NCIS has referenced Gibbs several times, but the show hasn't given much of an indication of his return. Harmon remains a key member of the show's creative team, as he is an executive producer and is still the first name that appears in the opening credits. While NCIS has shifted its focus to welcome the team's newest leader, Alden Parker (Gary Cole), to the action, it is clear that Gibbs looms large both for the characters and the fans of the CBS show.
Though nothing is officially in the works, it seems likely that Gibbs could return to NCIS in the future. Recently, longtime NCIS series star Sean Murray commented on the possibility that Harmon could put in another appearance at some point down the line, admitting, "I really, truly believe that the Gibbs could pop up somewhere." This is because Harmon does still return to the NCIS set and holds ties to the series. Now that Murray has agreed that a potential Gibbs reappearance could happen, the question now becomes this: what could possibly bring Gibbs back to the fray?
Considering Gibbs' fierce loyalty towards those he cares about, it seems that the most likely reason for his return would involve one of the main NCIS characters being put in danger. Gibbs is known for going above and beyond for his team members, whether that be by traveling to Somalia on a near-impossible mission (as seen with season 7's daring rescue of Ziva David) or getting involved in an off-the-books investigation for a friend when Tobias Fornell's daughter died. If NCIS were to seriously threaten someone like Timothy McGee (Sean Murray) or Vance (Rocky Carroll), Gibbs would almost certainly return to help them. Another potential way to draw him back would be to focus on a high-stakes plot that requires all hands on deck. However, assuming Harmon needs a really good reason to put in an on-screen appearance, a more personal and emotional story would likely be best.
NCIS has been renewed for at least one more season, so the upcoming season 19 finale will not be its final episode. Incidentally, the finale will put a main character - Parker - in a very difficult situation when he's framed for murder. This would be the kind of plot premise that could pull Gibbs back in. Not to mention that a season finale would be a good place for a surprise return. However, NCIS' Gibbs and Parker don't have the same kind of bond that Harmon's character has with, say, McGee, so the NCIS season 19 finale might not be the best place for him. Should CBS decide to end NCIS with season 20 or perhaps another season after that, the last episodes of this beloved series would also serve as the perfect return point for Gibbs, even regardless of the story they tell. In other words, there are plenty of opportunities ahead for a potential reappearance, provided Harmon is interested in breaking Gibbs' current happy ending.
NCIS airs new episodes Mondays on CBS.