Mark Harmon Weighs in on Casting for 'NCIS: Origins' Spinoff

Mark Harmon may have exited NCIS back on the fourth episode of Season 19, but his connection to all things NCIS is still going strong. In line with that, he will be releasing the second of two books that honors the work done by early NIS agents —Ghosts of Panama: A Strong Man Out of Control—on Nov. 19, which he co-authored along with Leon Carroll Jr., a technical advisor on NCIS and a former NIS agent. And then he serves as an executive producer and the narrator of the prequel series NCIS: Origins, which just received its full-season pickup.

“That's been fun,” Harmon tells Parade of taking on the narration, “because both [showrunners] Gina [Lucita Monreal] and David [J. North] have a long history with the show and I go way back with both of them So, me doing the narration was always going to be part of this, so that wasn't a surprise. What is the surprise is talking about Gibbs. Sometimes I don't have a lot of stuff to do in an episode and then sometimes I’ve got a boatload of stuff to do and that's putting words in the mouth of a character that traditionally said a lot with very little.”

When Origins was developed, it was always planned for Harmon to do the narration but what was not expected was him appearing on camera in the premiere episode to set up the reason for the narration—and it was a happy reveal for fans to see that Gibbs is still fishing in Alaska in present day and working on a journal.

“They were trying to figure out how to introduce the narrative and that’s the reason that birthed itself,” Harmon continues.

Related: NCIS: Origins Star Austin Stowell Reveals the Personal Tragedy He Used to Get Inside Gibbs’ Head

The reveal of what Gibbs is doing in 2024 was one of many Easter eggs that has been part of the launch of Origins. Others include Gibbs getting his first sip of bourbon, the first time he stopped an elevator for a private conversation, the fact that he always carries a knife, and more info on how Gibbs’ rules came to be.

“The intent always was to have great fun with that and there's so many,” Harmon agrees. “David and Gina are enjoying opening those up.”

Harmon adds that as much as he is a part of Origins, the role is now Austin Stowell’s and Harmon’s available and will be there any time his help is needed, but it’s now about another era in the Gibbs story, which he has little part in. Except, of course, he did help cast it.

Related: Mark Harmon on Why Austin Stowell Is the Perfect Young Leroy Jethro Gibbs for NCIS: Origins

“We're happy with the cast,” Harmon says. “Austin is a good kid and a nice actor. I think back to all the weeks we spent in casting offices trying to put that cast together and we couldn't be happier with this cast, but at the same time, I think back to the original show, say the first four years, and the molding of the show and how many changes there were in those first four years. There were huge changes, and you expect it's going to be no different on this that there'll be changes.”

The good news is the fact that now that NCIS: Origins received a full-season pickup with five additional episodes being added for a season total of 18, the series will have time to work out all the kinks.

NCIS: Origins airs Monday nights at 10 p.m. ET/PT on CBS.

Related: NCIS: Origins Showrunners on How Mark Harmon's Narration Takes Us Inside Gibbs’ Head