Mark Harmon, best known for his portrayal of Supervisory Special Agent Leroy Jethro Gibbs on the long-running series NCIS, will feature prominently in the upcoming third season of its spinoff, NCIS: Origins. Despite his departure from the original NCIS in 2021, Harmon remains integral to the franchise, returning as both narrator and executive producer, and is set to reprise his iconic role in every episode of the new season, which premiered on October 6, 2025.
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Harmon played Gibbs for nearly two decades, first introducing the character on the legal drama JAG in 2003, before NCIS debuted later the same year. After leading the show for 18 successful seasons, Harmon exited the series during Season 19, with his last appearance recorded in episode four. His departure was a significant moment for fans and the franchise, marking the end of an era.
Kelly Kahl, the former President of CBS Entertainment, noted shortly after Harmon’s exit that although he was no longer on-screen, he remained a vital part of the show’s identity. “Mark’s always been part of the show, Mark’s always going to be part of the show,” Kahl stated in an interview. The enduring popularity of Gibbs has allowed Harmon to re-enter the narrative with NCIS: Origins, which is set in 1991 and follows the earlier days of Gibbs’ career as a special agent, portrayed by Austin Stowell.
Reflecting on his decision to leave NCIS, Harmon emphasised the importance of timing and ensuring his character had a proper conclusion. In a special feature for the Season 19 DVD, he expressed appreciation for the character’s journey, leading him to conclude that his time on the show had come to a fitting close. “What has always drawn me [to NCIS] is the character I play and to keep that fresh and to keep it challenging,” he explained.
In a more candid discussion during a November 2023 appearance on The Kelly Clarkson Show, Harmon revealed that fatigue played a role in his decision to step away. He recalled the demanding nature of the show, stating, “I think for the longest time, I was just tired. The first day [on NCIS], we worked 22 hours.” He pointed to a need for balance in his life, especially as he neared 70, which led him to focus on his family and personal interests.
NCIS executive producer Charles Floyd Johnson also recognised the toll the demanding schedule took on Harmon. He praised Harmon’s commitment while noting the physical and emotional challenges of leading the show for nearly two decades. Johnson mentioned that Harmon had begun suggesting a potential exit as early as the 15th or 16th season, highlighting his dedication but also his need for a change.
Following Harmon’s departure, NCIS actor Sean Murray, who has played Special Agent Timothy McGee since 2003, reflected on filming Harmon’s final scene. “It was all too emotional, not just for me but for everyone involved,” Murray conveyed. This sentiment was shared among the crew, who found it difficult to say goodbye to a character whose presence had become synonymous with the show.
Gibbs’ exit from NCIS was crafted to allow for future appearances. In his final episode, Gibbs solved a high-profile case in Alaska before opting to remain there, thereby signalling a natural progression for his character’s life beyond the Bureau. This decision hints at the possibility of revisiting Gibbs, allowing Harmon to keep his connection to fans alive.
Since leaving his role on NCIS, Harmon has been actively involved in other projects. In late 2023, he announced the release of a new book titled *Ghosts of Honolulu*, co-written with former NCIS technical advisor Leon Carroll Jr. Additionally, he made a guest appearance as Ryan Coleman alongside Jamie Lee Curtis in the upcoming film *Freakier Friday*.
Harmon’s ongoing connection to the NCIS franchise through *NCIS: Origins* has allowed him to continue exploring the character of Gibbs in depth. He is expected to delve into a present-day mystery linked to his character’s adventures in the 1990s throughout the third season, promising viewers an action-packed narrative that ties back to the foundational storytelling of the original series.
As Harmon prepares to return as a regular cast member in NCIS: Origins, anticipation builds among fans for his portrayal of Gibbs and the new layers to his character that will be revealed in this format. Moreover, with his son, Sean Harmon, making an appearance as FBI Agent Casey Bloom, the family connection continues, adding a new dimension to the show’s dynamic character relations.