The origin story of Leroy Jethro Gibbs has finally begun: CBS kicked off its much-anticipated prequel Monday from veteran NCIS writers-producers Gina Lucita Monreal and David J. North, as well as CBS Studios. And as promised, Mark Harmon returned to both narrate and to appear fireside as he journals about his life.

Go back in time as a young Leroy Jethro Gibbs begins his career as a newly minted special agent in the new CBS series "NCIS: Origins."

Origins two-part premiere “Enter Sandman” are ahead! NCIS: Origins has finally premiered on the 2024 TV schedule, mean the time has finally come to explore Leroy Jethro Gibbs’ life in 1991, just a few months after his first wife and daughter were murdered.