For years, Mark Harmon remained the steadfast heart of NCIS, portraying the stoic and beloved Leroy Jethro Gibbs. But behind the scenes, Harmon was fighting a private battle—one he never intended for the public to see. Recent revelations have confirmed long-standing whispers: Harmon was quietly dealing with a serious health issue during his final seasons on the show.

Those close to the actor say he was determined not to let his condition affect the cast or production. He continued showing up to work, never missing a beat, even when the physical toll became increasingly difficult to hide. Crew members noticed his weight loss and occasional fatigue, but Harmon brushed off concerns, attributing it to “just getting older.”

It wasn’t until after his departure from NCIS that the truth began to surface. According to insiders, Harmon had been undergoing treatments and was advised to slow down, ultimately leading to his emotional decision to step away from the show. Fans who were devastated by his exit are now seeing it in a new light—his choice wasn’t just about storylines, but about survival.

Now, with the truth out, there’s an outpouring of support for Harmon. His courage to keep going while in pain, all to protect the integrity of the show and the people he worked with, only deepens the admiration fans feel for him.