Origins (and how old Mark Harmon and Austin Stowell are)

Leroy Jethro Gibbs is one of the most iconic characters in the NCIS franchise, as Mark Harmon played him in 19 seasons of the original show. However, Gibbs returned in the 2024 prequel series NCIS: Origins, with Austin Stowell playing a younger version of the NCIS agent, further cementing the character's legacy. Harmon even reprises his role as the older Gibbs in NCIS: Origins, both physically and vocally as he narrates the prequel.

Harmon's Gibbs left NCIS at the beginning of season 19, when he decided to stay in Naktok Bay, Alaska, where he finally found peace. However, it appears that the NCIS the franchise cannot live without Gibbs. CBS premiered the NCIS prequel NCIS: Origins in the fall of 2024, with Stowell taking over the role of Gibbs. The actor plays a younger version of the character at the beginning of his career in 1991.

Gibbs is 49-67 in his NCIS run

Gibbs' birthday is November 21, 1954

NCIS premiered in 2003, probably the year the first season took place. Of course, Harmon made his debut as Gibbs in NOTCH, but even those episodes were in 2003. So since Gibbs' birthday is known (November 21, 1954), it stands to reason that the character was around 49 years old at the start of NCIS.

If the show's events happened in real time, that would mean that Gibbs was about 67 years old when he left the Naval Criminal Investigative Service and moved to Alaska in season 19, episode 4. Harmon's ending NCIS episode aired in the fall of 2021, placing his character in his late sixties. Meanwhile, Stowell's version of Gibbs is more than a decade younger than Harmon's when he began playing Gibbs in the early 2000s.

Gibbs is 37 years old on NCIS: Origins

NCIS: Origins begins in 1991

CBS confirmed that NCIS: Origins starts in 1991, meaning Stowell's Gibbs is 37 years old in the prequel. THE NCIS: Origins the character is 12 years younger than Gibbs was in the original series' first season, which makes sense given how different the two portrayals of him are. Stowell's Gibbs is in a very different place in his life and career. Gibbs' wife and daughter recently died and he has just started his job at the NIS Camp Pendleton office. He is centuries away from the person he was in 2003.

Mark Harmon is 73 and Austin Stowell is 39

Both actors are close to Gibbs' age in their respective eras

Although most TV shows like to cast older actors to play characters much younger than themselves, NCIS I'm very close in age to Gibbs. Harmon, whose birthday is September 2, 1951, is 73 years old. He was 52 when he started playing Gibbs, while the character was 49. As for Stowell, whose birthday is December 24, 1984, the actor is just two years older than Gibbs. NCIS: Origins season 1. Hopefully CBS will renew the NCIS show, and Stowell will continue Gibbs' legacy for many anniversaries to come.