Mark Harmon will take on a significantly larger on-screen role in Season 3 of NCIS: Origins, reprising Leroy Jethro Gibbs throughout the entire upcoming season after previously serving primarily as the prequel’s narrator and executive producer. CBS confirmed that Harmon will appear in all episodes when the series returns this fall, marking his most extensive involvement in the spinoff since it debuted.

The new season will center on a present-day storyline involving the veteran Gibbs that connects to his early years at Camp Pendleton during the 1990s, with the mystery unfolding over the course of the season. Harmon previously appeared briefly in the series premiere and later returned during the first crossover between NCIS and NCIS: Origins, but Season 3 will be the first time his character is woven into the show’s ongoing narrative from beginning to end.

Harmon portrayed Gibbs on the flagship NCIS for 18 seasons before stepping away as a series regular in 2021, though he has remained closely connected to the franchise behind the scenes. NCIS: Origins follows a younger Gibbs, played by Austin Stowell, as he begins his career with the Naval Investigative Service in the early 1990s. The cast also includes Kyle Schmid, Mariel Molino, Tyla Abercrumbie, Diany Rodriguez and Caleb Foote.

The announcement follows a dramatic Season 2 finale that left multiple storylines unresolved, including Randy’s kidnapping and the evolving relationship between Gibbs and Lala, setting the stage for the next chapter. According to CBS, Harmon’s return will help drive the season-long investigation while adding a present-day perspective to the prequel’s events. Season 3 is scheduled to premiere this fall on CBS, with streaming availability on Paramount+.

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