For most of its run, when anyone remotely familiar with NCIS would think of the series, chances are Mark Harmon would be the first person to come to mind. After all, he led the popular CBS show for 18 full seasons as Special Agent Leroy Jethro Gibbs, then exited early into Season 19 back in 2021. While NCIS is still going strong these days, one of the show’s executive producers reflected on when he thought that Harmon leaving was going to be “the death knell.”
Charles Floyd Johnson discussed this subject while taking part in THR’s oral history’s of NCIS to commemorate its 20th anniversary, as well as opened up about why the St. Elsewhere alum decided to leave the show after nearly two decades:
We thought [Harmon leaving] was the death knell. Coming in at 6:30 a.m., five days a week, and being the major character that was the linchpin — that’s pretty tough, and he did it for 18 seasons. He had just gotten to the place where he was getting close to turning 70, and he wanted to spend time with [wife] Pam [Dawber] and his kids. So he was leading up to it. It started probably [with him dropping hints] around the 15th or 16th season. But he was so loyal to that crew and so supportive of the show. He was very proud of it, and he stayed on longer than he even intended.
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While Mark Harmon certainly isn’t the only lead actor to leave a TV show before it’s wrapped up, more often than not, shows that endure such casting shakeups rarely keep up its quality level (I’m looking at you, The X-Files and The Office). So I can understand where Johnson was coming from worrying that Harmon exiting NCIS might lead to the series ending, but on the other hand, given Harmon’s age and wanting to spend more time with his family, you can’t fault the man for eventually deciding that it was time to leave. After all, it’s impressive enough when an actor gets to play a role on TV for more than just a few seasons, and he brought Gibbs to life for well over a decade and a half.
Ultimately, Harmon was willing to wait a few extra years before heading out, but by Season 18, seeds started being planted for his exit, and he made his last NCIS appearance in Season 19’s fourth episode, “Great Wide Open,” where Gibbs decided to stay in Alaska and finally felt at peace for the first time since his first wife and daughter were killed. Shortly afterwards, Gary Cole’s Alden Parker succeeded Gibbs as team leader, and Charles Floyd Johnson said this about how well Cole’s casting worked out:
In the end, we hit gold with Gary Cole. There were a lot of names bandied about. When everybody finally decided we’d make an offer to Gary Cole, we didn’t pitch it to him as, ‘He was going to become the new Gibbs.’ We pitched it to him that he was going to come in and wasn’t sure he was going to stay with the team, so that he didn’t have to feel like he was stepping into the shoes of someone who had been there for 18 seasons.
Fellow executive producer Mark Horowitz added that Alden Parker serves as a nice contrast to Leroy Jethro Gibbs, because while “everybody was pretty much under” the former when he was leader, the latter coming in allowed for things to loosen up “a little bit,” which included allowing Sean Murray’s Timothy McGee to become a senior agent. As for whether Harmon could return to NCIS someday as a guest star or recurring player, that’s hard to say, because as of this past July, there was allegedly some behind-the-scenes drama surrounding a potential return.
Fortunately, there are hundreds of NCIS episodes starring Mark Harmon that can be enjoyed with a Paramount+ subscription. Meanwhile, read through our 2023 TV schedule to see what new programming is airing now while we wait for updates on what’s in store for NCIS Season 21.