Mark Harmon expressed his amazement at the enduring success of “NCIS” and its ability to maintain quality throughout its long run. Even in the early seasons, Harmon was surprised that the show avoided the common pitfalls faced by other long-running series. In an interview with TV Guide, he noted that it’s unusual for a show to remain exciting and maintain high viewership after 12 years.
Harmon credited the show’s success to the camaraderie among the cast and crew. Speaking on The Late Show with Stephen Colbert, he emphasized the importance of working with people who love their jobs and feel a sense of responsibility. According to Harmon, the key to the show’s longevity is the dedication of the team.
Despite acknowledging that every show has its time, Harmon believed that the fate of “NCIS” would be determined by the writers. In a 2019 interview with People, he expressed the view that if the writers ever felt stuck, it might be time to call it a day. At that time, Harmon considered “NCIS” to be the peak of his career and expressed doubt that a better opportunity would come along after the series concluded.
While Harmon initially seemed committed to staying with “NCIS” until its end, he eventually decided to leave the show after 19 seasons as Jethro Gibbs. In his departure statement, as reported by Entertainment Tonight, Harmon mentioned that his decision was influenced by the need to keep the character fresh and challenging. Despite his initial plans to stay, Harmon believed it was honest and appropriate for the character to take a different path.