NCIS Was Originally Built On A Different Premise, According To Mark Harmon

Mark Harmon exited "NCIS" after 19 seasons in 2021, but he arguably remains the face of CBS' long-running, naval-themed procedural saga. After all, he joined the franchise in the days of "JAG," and his Leroy Jethro Gibbs character was an "NCIS" mainstay for almost two decades. As such, he remembers the creators' original plans for the show, which were a little different from what "NCIS" ultimately became. So, what was Harmon sold on in the beginning?

"When I first joined the show, part of what they sold me on was that this was all going to be based on real cases," Harmon recalled in an interview with The Hollywood Reporter. "But pretty soon, it settles into murder-a-week because that's television, right?"

Harmon added that he was asked to write a book about "NCIS," but it never interested him, as he was more interested in documenting real-life cases. Fortunately, Harmon has been able to indulge his interests in the actual Navy through his non-fiction writing, notably in his "Ghosts of Panama" book. Despite "NCIS" not being what he originally signed up for, though, the Gibbs actor is more than happy with how the show turned out.

"NCIS" has over 1,000 episodes to its name, which is a remarkable achievement for any TV show. As it stands, it is one of the longest-running primetime dramas in the history of American television, so the murder-of-the-week formula has clearly paid off and then some. Mark Harmon is more than happy with what the series became, but he still remembers the days when it looked like the CBS procedural might not grow into a hit.

"I'm thrilled the show has been as successful as it's been. The first day on the show, we worked 22 hours, so that wasn't exactly what I had in mind," Harmon added in the aforementioned THR interview. "There were a lot of changes in those first three or four years. People don't realize that, but this show didn't jump out."

Mark Harmon has portrayed Gibbs in the "NCIS" franchise again since parting ways with the main series in 2021. His character narrates the "NCIS: Origins" prequel series, and Harmon's present-day Gibbs shows up for a couple of blink-and-you-will-miss-them cameos. It remains to be seen if he will return to the franchise in a more meaningful on-screen capacity, but fans can rest assured knowing that he is still involved in some way.