Sean Harmon, son of Mark Harmon, came up with the concept for NCIS: Origins while playing young Gibbs. Now, the prequel series will dive into the early days of the iconic agent in the Naval Criminal ...

Mark Harmon has grown to become a TV veteran thanks to his role on NCIS as agent Leroy Jethro Gibbs, a character he portrayed ...

Mark Harmon captained the flagship NCIS for 18 years ... Photo: Getty Images Mark pictured with his wife Pam Dawber Given that Mark and Pam's sons – Sean, 36, and Ty, 31 – have left the ...