Mark Harmon, who previously departed the flagship NCIS series in 2022, is set to significantly expand his role in the prequel spin-off NCIS: Origins. The 74-year-old actor will appear as an older version of his iconic character, Leroy Jethro Gibbs, in every episode of the show's upcoming third season, according to TVLine.
The series, which stars Austin Stowell as a younger Gibbs, chronicles the early years of the special agent before he became the NCIS team's leader. Harmon's appearances will be integrated into a present-day storyline that connects to a mystery from Gibbs' time at Camp Pendleton in the 1990s. He also continues to serve as an executive producer and narrator for the project.
Harmon's return marks an expansion from his previous guest appearances on NCIS: Origins. He appeared in the show's 2024 premiere and made a surprise comeback during a 2025 crossover event with NCIS on CBS, which was his first on-screen acting role in four years since stepping back from the main series. His involvement in the crossover was prompted by a compelling pitch from co-showrunners David J. North and Gina Lucita Monreal, Harmon stated.
"They came to me with an idea for Gibbs that I liked, and it seemed like a good time to check in with him," Harmon said. "I hope fans enjoy it."
Fans have expressed significant excitement on social media regarding Harmon's increased presence. Comments ranged from enthusiastic declarations of enjoyment to relief at seeing the actor back on screen.
Harmon initially portrayed Gibbs for over 18 seasons on NCIS, departing the flagship series in 2021. His character moved to Alaska in the episode "Great Wide Open." Showrunner Steven D. Binder previously commented on Harmon's departure, stating that the actor remained an "integral part of the fabric of the show" and that Gibbs' story was not necessarily concluded.
Harmon's acting career spans decades, with earlier roles including Fielding Carlisle on "Flamingo Road" and appearances in "St. Elsewhere." He also featured in films such as "Let's Get Harry" and "Summer School" before landing the role of Gibbs in 2003. His portrayal of Gibbs earned him multiple People's Choice Award nominations and a win for Favorite TV Crime Drama Actor in 2017. In 1986, he was named People magazine's Sexiest Man Alive.
He is married to actress Pam Dawber and they have two sons, Sean and Ty.