Mark Harmon to Make Guest Appearance as Gibbs on NCIS: Origins 4 Years After Exit from Franchise

Mark Harmon is back at Camp Pendleton.

The veteran actor, 74, will be guest starring in the first-ever NCIS and NCIS: Origins crossover event on Tuesday, Nov. 11. The actor, who played Leroy Jethro Gibbs for 18 seasons on the original series before exiting in 2021, will make his first on-camera appearance since his cameo in the prequel’s debut in 2024.

“In the crossover event airing on Veterans Day, younger Gibbs (Austin Stowell) and team investigate the small-town death of a naval officer in the ‘90s on NCIS: Origins – a case that’s unexpectedly re-opened in the present day on NCIS,” the official synopsis reads. “The decades-spanning mystery finds the air order for the series switching for one night only.”

While this marks Harmon’s return to the screen, he has remained involved in the franchise, serving as an executive producer of both shows and the narrator of each episode of Origins.

“Four years ago, Gibbs disappeared to Alaska to live a life of solitude,” said co-showrunners and executive producers David J. North and Gina Lucita Monreal in a press release. “We know how much fans have missed seeing Mark and have wondered what Gibbs is up to today. Well, on Nov. 11, we’re so excited to announce that Mark Harmon will return as Leroy Jethro Gibbs in the Origins hour of the NCIS crossover event.”

“We don’t want to give too much away, but let’s just say Gibbs is no longer alone,” they teased.

In a separate statement, Harmon commended North and Monreal for their powerful “storytelling.”

“They continue to push boundaries and dive deeper into the characters’ backstories,” he said. “They came to me with an idea for Gibbs that I liked, and it seemed like a good time to check in with him. I hope fans enjoy it.”

Origins, which is currently on its second season, takes place in the ’90s, following the early career of a young Leroy Jethro Gibbs, played by Stowell, prior to the events seen in NCIS. Harmon originated the role of Gibbs in 2003 when NCIS first premiered and continued to portray the beloved character until his departure in 2021.

Along with Stowell, the spinoff also stars Kyle Schmid, who plays the younger version of Special Agent Mike Franks (originally played by Muse Watson), and Mariel Molino as Special Agent Cecilia “Lala” Dominguez.

NCIS: Origins will air first at 8 p.m. ET, followed by NCIS at 9 p.m. ET on CBS and streaming on Paramount+ (live and on demand for Paramount+ Premium plan subscribers, or on demand for Paramount+ Essential subscribers the day after the episode airs).