One of his first acting roles was in a would-be spinoff of the classic drama.

The upcoming NCIS and NCIS: Origins crossover brings Mark Harmon back onscreen as Leroy Jethro Gibbs, though his presence remains a constant part of the prequel. He serves as an executive producer and ...

Mark Harmon may have left NCIS, but he'll forever be synonymous with Supervisory Special Agent Leroy Jethro Gibbs. "Mark's always been part of the show, Mark's always going to be part of the show," ...

Aya Tsintziras is a freelance writer who writes about TV, movies, and has a particular interest in the horror genre. She has a Political Science degree from the University of Toronto and a Masters of ...

"NCIS" legend Mark Harmon is bringing his OG Leroy Jethro Gibbs character to the prequel series "NCIS: Origins," and he's not coming alone. Harmon, 74, will make a rare guest appearance on "Origins" ...

(CBS) - Mark Harmon will make a special guest appearance as Leroy Jethro Gibbs on NCIS: Origins on Nov. 11. Harmon played Gibbs for 18 seasons on NCIS. In the crossover event airing on Veterans Day, ...