Sean Harmon set to guest star in ‘NCIS: Origins,’ but not as his ‘NCIS’ role

Sean Harmon will play a brand-new role in ‘NCIS: Origins’ Season 3, Episode 2, titled ‘My Own Worst Enemy’

'NCIS: Origins' is bringing back a familiar face from the franchise, but in a completely different role. According to a press release by Paramount, 'NCIS: Origins' will welcome Sean Harmon as a guest star in Season 3, Episode 2, titled 'My Own Worst Enemy,' airing Tuesday, October 13. Sean previously played a younger Gibbs in several flashback sequences in the series. He has appeared in eight episodes as the character. But in the prequel, he will play FBI Agent Casey Bloom. This is not surprising, as the prequel follows a young Gibbs, played by Austin Stowell, as a Probationary NIS Agent in the 1990s.

A still of Ducky and Gibbs from 'NCIS'
A still of Ducky and Gibbs from 'NCIS' — (Image Source: CBS)

The episode description is out, and it will feature Mark Harmon as an older Gibbs. No clarity on Sean's role has been provided apart from the name. The father and son may appear on-screen together for the first time in the franchise. The episode's logline reads, "In the present, Gibbs (Mark Harmon) returns to civilization and calls in a favor from old friend Woody (Bobby Moynihan). In 1992, the team bands together to help Woody when he's accused of murdering a bowling rival."

A still of Lala and Gibbs from 'NCIS: Origins' (Image Source: CBS | NCIS: Origins)
A still of Lala and Gibbs from 'NCIS: Origins' (Image Source: CBS | NCIS: Origins)

In 2024, when the prequel premiered, fans were a bit shocked that Sean did not reprise Gibbs; instead, the team hired a new actor. Mark Harmon shared with Variety that it was Sean's call. "He's an actor, writer, producer, a surfer; he does a lot of things. You have to come to decisions about what you want to do in life, or what you think's important. I just think he made a choice and had to make a decision in some ways. He likes executive producing," Mark explained. Sean remains on board as an executive producer. 

A still of Gibbs from 'NCIS'
A still of Gibbs from 'NCIS' — (Image Source: NCIS)

Season 3 of the prequel features a season-long arc for the older version of Gibbs played by Mark. The show will constantly switch between present and past timelines. "When we first see Gibbs in the season premiere, he is still in Alaska with his trusted rescue dog but soon finds that the peace he found there isn't going to be easy to hold on to. Ghosts from his past are catching up to him, and it may be enough to pull him out of retirement. Over the course of the season, we'll discover that what's happening in present day is directly tied to events that occurred during his '90s Camp Pendleton days," showrunner and executive producer David J. North shared with Deadline regarding Gibbs' return. 'NCIS: Origins' will return with its third season premiere on Tuesday, October 6 at 10 p.m. ET/PT on CBS. 

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