Before NCIS: The Untold Story of Mark Harmon’s Rise to Fame

Mark Harmon might forever be linked with NCIS's Leroy Jethro Gibbs, but that's just one part of a life filled with unexpected turns, personal discipline, and a quietly impressive career.

He was the anchor of one of TV's most-watched dramas for nearly two decades. Fans knew the Gibbs stare, the head slaps, the boat-building, and his unwavering loyalty to the team. What most people don't realize? Harmon had already lived a few lives before the first NCIS script hit his hands.

First Love: Football

Long before scripts and studio lights, Harmon's life revolved around football. It wasn't just a hobby—it was a legacy.

His father, Tom Harmon, was a famous football player in the 1940s. Later, he became a well-known broadcaster. Mark developed a love for football early on. By the time he joined UCLA in the early 1970s, he was already starting to make a name for himself. He did more than just play; he took on a leadership role. As the starting quarterback for the Bruins in 1972 and 1973, he showed strong and calm leadership that his teammates respected.

Decades later, in 2019, he was honored with the National Football Foundation Gold Medal, a nod to his athletic chops and the integrity he carried with him off the field.

"Watching my dad broadcast those games… there was a magic to it," Harmon once told Parade.

That sense of presence—being grounded and collected—would become a Harmon trademark, both on-screen and off.

Early Acting Days: Taking the Scenic Route to Stardom

Acting wasn't the original plan. But life, as it tends to, redirected him.

Harmon entered the industry thanks to his brother-in-law, Ricky Nelson, and Nelson's famous parents, Ozzie and Harriet. It started casually. Ozzie asked Mark to fill in for a missing actor on a sitcom episode. Harmon said yes. That's how it started—just one line, one moment. But it changed everything.

Soon, Harmon was picking up guest spots on shows like:

• Emergency!
• Laverne & Shirley
• Police Woman
• The Hardy Boys

By the end of the '70s, he'd stacked up a dozen TV credits—not blockbuster roles, but enough to prove he had something. It was a natural ease on camera, even when the parts were small.

The '80s: Breakthroughs, Bold Roles & Sexiest Man Alive

If the '70s were about earning his stripes, the 1980s were about big swings.

In 1983, Harmon joined St. Elsewhere as Dr. Robert Caldwell, a plastic surgeon with a complex personal life. Unlike most medical dramas at the time, the show was gritty and witty, and his character became part of a landmark moment in television. Caldwell was the first significant TV role to die from AIDS-related complications off-screen. It was a bold move by the writers—and by Harmon.

"People still bring it up. It mattered to them," he later said in an interview with Variety.

Around that time, Harmon also took on a much darker role, playing Ted Bundy in The Deliberate Stranger. It was an eerie, convincing performance, and critics took notice. That same year, People crowned him Sexiest Man Alive—which, depending on who you ask, either helped his image or made it harder for folks to see past the jawline.

Steady Roles, Subtle Growth: The '90s Grind

The '90s weren't filled with mega-hits, but they showed something else about Harmon: consistency.

He starred in crime drama Reasonable Doubts as Detective Dicky Cobb, then popped up in Charlie Grace, and later joined the cast of Chicago Hope as Dr. Jack McNeil, a role that let him show some real range. He even directed a few episodes, dipping a toe into the other side of the lens.

But one of his shortest gigs made the biggest impact: a four-episode arc in The West Wing, where he played Secret Service Agent Simon Donovan.

"I got a scene faxed on a Wednesday, and by Thursday morning, I was on set," Harmon recalled.

That performance earned him an Emmy nomination—and, more importantly, caught the eye of Donald P. Bellisario, the mind behind JAG and, eventually, NCIS.

2003: The Arrival of Gibbs

In 2003, Harmon first appeared on JAG as Special Agent Gibbs—a stoic, no-nonsense federal agent with a piercing gaze and a past full of ghosts. That guest spot led directly into NCIS, where Harmon would stay for nearly 20 years.

It wasn't just a role. It was a reinvention.

As NCIS became a global juggernaut, Harmon became the quiet leader on and off screen. By 2008, he was executive producing the show and eventually got involved with NCIS: New Orleans.

It wasn't with fanfare or drama when he stepped back in Season 19. It was just a quiet shift—like Gibbs would've done it.

"Never count Gibbs out," said showrunner Steven D. Binder (via ET).

Final Thoughts: A Legacy Built on Stillness and Strength
Mark Harmon didn't build his career on hype. There were no big scandals, no explosive interviews. Just work—steady, brilliant, solid work.

From quarterbacking at UCLA to redefining what a TV cop could be, Harmon built something rare in Hollywood: a reputation for showing up, getting it done and letting the rest speak for itself.

And even now, with his role on NCIS winding down, one thing’s for sure: He’s not done yet.