Why Mark Harmon Almost Left NCIS After Season 4

Despite the show’s massive ensemble cast, the first character that comes to mind from “NCIS” is Leroy Jethro Gibbs (Mark Harmon). The stern former Marine Sniper steers the NCIS Major Case Response Team with a fatherly hand, establishing himself as the show’s face and de facto lead during his 19-season tenure with the show. 

However, things almost didn’t play out this way. In fact, Harmon was very close to walking away from the show a mere four seasons into its run. According to TV Guide’s Michael Ausiello, the reason behind the “NCIS” star’s near-exit was the procedural’s co-creator and original showrunner, Donald Bellisario. Per Ausiello’s anonymous source, Bellisario’s tardiness with the show’s scripts and tendency to over-involve himself was a source of great frustration to Harmon, prompting the star to consider an exit after season 4:

“Mark’s been working every single day, 16 hours a day. Don tries to micro-manage everything. Script pages get faxed to the set at the last minute, and Mark is tired of dealing with the huge impact that makes on his life.”

As history shows, the reported clash between Bellisario and Harmon ended in the latter’s victory. In 2007, Bellisario moved to a more hands-off executive producer role. Leroy Jethro Gibbs, on the other hand, soldiered on. Before Harmon left “NCIS,” he worked with multiple other showrunners. After Bellisario, eventual “NCIS: Los Angeles” creator/showrunner Shane Brennan took over the reins on the flagship show for two seasons. When Brennan moved to the L.A. leg of the franchise full-time in 2009, Gary Glasberg took over from “NCIS” season 7 onwards, and after Glasberg’s tragic death in 2016, George Schenk and Frank Cardea have acted as co-showrunners. 

Bellisario, however, is the only showrunner Harmon reportedly had serious issues with during his tenure playing Gibbs — and the situation seemed to be quite mutual. In a 2008 interview with the Los Angeles Times, Bellisario lifted the lid on his side of the pair’s relationship during season 4, alleging that the “NCIS” star refused to play along with a reshoot request and ultimately shut the showrunner out altogether:

“I asked Mark to re-shoot a scene. He redid it exactly the same way he did it the first time and never spoke to me again.” 

Gibbs went through a fair few hurdles on his way to become the 19-season military procedural icon we now know him as. Not only did Harmon’s character originally have a totally different name on “NCIS,” the makers of the show actually considered several other actors to play Gibbs before him. However, eventually the stars aligned, birthing a TV presence so powerful that he’s able to take down evil-doers and showrunners alike.