Mark Harmon exits CBS' long-running NCIS after more than 18 seasons while remaining on board as an executive producer

• Mark Harmon's exit as Leroy Jethro Gibbs was confirmed on Monday night's episode of NCIS 
• The actor had been starring in the action show for 18 seasons 
• It's possible that we haven't seen the last of Gibbs, but he most certainly won't be a weekly presence on the show as he has been for the past 18 seasons 
• NCIS executive producer Steve Binder released a statement about Harmon leaving the show, confirming that Harmon still will serve as an executive producer himself 
• NCIS was a spin-off of CBS' JAG, both of which were created by Donald P. Bellisario, which ran for 10 seasons between 1995 and 2005 

After months of rumors about his 19th season on NCIS, Mark Harmon's exit as Leroy Jethro Gibbs was confirmed on Monday night's episode Great Wide Open.

There had previously been reports that the 70-year-old actor will only appear in a few episodes this season, with his exit cemented in the episode.

Still, it's possible that we haven't seen the last of Gibbs, but he most certainly won't be a weekly presence on the show as he has been for the past 18 seasons.

The episode followed Gibbs solving a case of a conglomerate CEO hiring a contract killer to take out those opposed to a copper mine.

When Gibbs was offered his badge back by Leon Vance (Rocky Carroll), Gibbs revealed he was leaving the agency, choosing to stay in Alaska, where he'd been for the past few episodes.

NCIS executive producer Steve Binder released a statement about Harmon leaving the show, confirming that Harmon still will serve as an executive producer himself.

'As an executive producer and dear friend, Mark continues to be an integral part of the fabric of the show,' Binder began.

'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,' Binder added. 

'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,' Binder concluded.

Harmon's final episode also solved a long-running mystery of the show, revealing how Gibbs gets his boats out of the basement.

FBI Agent Parker (Gary Cole) stopped by Gibbs' home after he had gone AWOL, telling Timothy McGee (Sean Murray), 'something tells me he’s not coming back.'

He was then seen staring at the large hole in the back of his house, which is large enough for Gibbs to get his boat out of.

There were rumors that Harmon was not going to return for the 19th season, though it's believed that he came back because he learned CBS might not renew the show if he didn't return. 

NCIS was a spin-off of CBS' JAG, both of which were created by Donald P. Bellisario, which ran for 10 seasons between 1995 and 2005.

The show ended up spawning a number of CBS spin-offs itself, NCIS: Los Angeles, which debuted in 2009 and is currently in its 13th season, NCIS: New Orleans, which was canceled after seven seasons, and NCIS: Hawaii, which debuted this fall.