Mark Harmon ‘Wouldn’t Touch’ His New ‘NCIS’-Inspired Project Without This Person by His Side

NCIS fans adored Mark Harmon as Leroy Jethro Gibbs, and they were devastated to see him exit the series in season 19. Now that Harmon has had some time away from NCIS, he’s reflecting on his lengthy time on the series. Recently, he mentioned that he would’ve never “touched” his 2023 book, Ghosts of Honolulu, without this one person by his side. Here’s who it is.

‘NCIS’ star Mark Harmon said he ‘wouldn’t touch’ his new book without technical advisor Leon Carroll Jr.

NCIS star Mark Harmon had a pivotal role in the series as Leroy Jethro Gibbs, and fans will never forget his incredible contributions to the series. While Harmon’s acting skills brought Gibbs to life, he was greatly helped by Leon Carroll Jr. Carroll Jr., a technical advisor with the show and a real retired NCIS agent who worked for the NIS/NCIS agency for two decades.

Harmon spoke on The View about his experience first joining NCIS, and he called Carroll Jr. his “guy,” as Carroll Jr. helped him learn and understand what the NCIS was really about.

“When I first got the job, when I first Googled ‘NCIS,’ there was no information on it,” Harmon explained. “That’s by design, because these individuals have been around for a long time. And they did very quiet, very important work, and nobody knew about it, and nobody talked about it. And so, when I got on the set, the first [person] really, I met, was Leon Carroll Jr. And he was my guy. … He’s the real deal, I’m the actor. And what he did, important job, quietly, for so many years.”

Harmon and Carroll Jr. wrote Ghosts of Honolulu: A Japanese Spy, A Japanese American Spy Hunter, and the Untold Story of Pearl Harbor together. And Harmon explained on The View that he never would’ve “touched” the project without Carroll Jr. by his side.

“When we talked about the idea of doing a book, because the show was originally based on real cases, we actually just went through history and went back to what was the beginning of what was NCIS,” Harmon continued. “… I said initially I wouldn’t touch this project without Leon Carroll Jr. He’s my partner, and I love the man.”

Leon Carroll Jr. has a ‘deep appreciation’ for the Leroy Jethro Gibbs actor

Mark Harmon and Leon Carroll Jr. got to know each other through NCIS, and they built a deep bond as they grew together in the series. After working on Ghosts of Honolulu together, they built an even greater appreciation for each other.

“Through an 18-year relationship, Mark and I have developed a deep appreciation of what we can do together as a team,” Carroll Jr. told People. “Considering different options and approaches to storytelling is similar, whether it is a book or a television show.”

Harmon feels grateful that he had the chance to share the more authentic side of the NCIS. “On the show, we used to use the fact that no one knew who this agency was or what they did as a point of humor, but for those doing this difficult job for real, there was nothing funny about it,” Harmon added. “To provide these men and women a chance to tell their story, their real story, has been both fun and educational for me.”

Mark Harmon reflected on feeling ‘tired’ after leaving ‘NCIS’

Mark Harmon is grateful for his time as Leroy Jethro Gibbs in NCIS. But immediately after calling it quits, he reflected on how he felt “tired” after so many years with the series.

“I think for the longest time, I was just tired,” Harmon told Kelly Clarkson on The Kelly Clarkson Show. “Originally, part of it, taking the job, being home for a young family, not traveling as much, doing movies and whatever, the first day, we worked 22 hours. So, I thought, ‘That’s not exactly what I thought this was going to be.’ We had a lot of days like that in the first four years.”

Harmon has no immediate plans to rejoin the series we know of. But the executive producers would certainly welcome him with open arms.

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