**Sean Harmon Set to Guest Star in Upcoming Episode of NCIS: Origins**
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Mark Harmon, a familiar face to fans of the NCIS franchise, is set to make his return as Special Agent Leroy Jethro Gibbs, not only in the flagship series but also in its prequel, NCIS: Origins. Recent announcements have confirmed that his son, Sean Harmon, will make a guest appearance in the much-anticipated second episode of the third season of NCIS: Origins, titled “My Own Worst Enemy”. This episode is scheduled to air on 13 October 2024.
Sean Harmon, 38, has taken on the role of FBI agent Casey Bloom in the upcoming episode, a character whose interactions with the seasoned Gibbs have yet to be disclosed. The generational connection between the Harmon family adds an intriguing layer to the series, as Sean previously portrayed a younger version of his father’s character in the mainline NCIS show.
The plot of “My Own Worst Enemy” will see Gibbs navigating a return to a familiar world, calling upon an old acquaintance, Woody, played by Bobby Moynihan. The storytelling ventures into a timeline set in 1992, where Gibbs’ team rallies to help Woody, who finds himself accused of murdering a rival at a bowling event. Laura Valdivia has penned the episode, with Jessica Lowrey directing, ensuring an engaging narrative focussing on friendship and loyalty.
In a notable collaboration, Sean Harmon also serves as an executive producer for NCIS: Origins alongside his father. This marks a shift from only acting, reflecting Sean’s ambitions within the industry. Mark Harmon previously discussed his son’s evolving career path, stating that Sean has shifted his focus towards producing, engaged in various pursuits including acting, writing, and surfing. It appears that he has found fulfilment in the role of executive producer, indicating a shift in his professional priorities.
This latest announcement comes three months after CBS confirmed Mark’s return for the full season of NCIS: Origins, promising fans a rich storyline that intertwines past secrets with present-day mysteries. This extended engagement marks a significant shift from his previous appearances in the series, allowing for deeper character development and narrative exploration in a season that promises to be action-packed.
Mark’s portrayal of Gibbs has resonated with audiences for 18 seasons of NCIS, beginning in 2003 and concluding his regular run in 2021. Having first returned briefly during a crossover event in November 2025, fans are eagerly awaiting more screen time with this iconic character. In previous interviews, Mark hinted at revealing new aspects of Gibbs’ life, providing viewers an opportunity to gain insights beyond what they already know.
The third season of NCIS: Origins is positioned to captivate audiences with new and returning narratives, airing every Tuesday at 10 PM ET on CBS, following NCIS: New York at 9 PM ET and the flagship NCIS at 8 PM ET. Additionally, for those wishing to catch up or watch new episodes, the series will be available for streaming on Paramount+ starting from 6 October 2024.
As the Harmon family continues to contribute to the legacy of the NCIS franchise, fans remain eager to see how both Mark and Sean will deliver their performances and creatively collaborate behind the scenes. Whether in front of the camera or behind the scenes, the ongoing family connection within NCIS promises to enrich the storytelling landscape for dedicated viewers as Season 3 unfolds.