How The West Wing Unexpectedly Gave Us Gibbs: The Surprising Role That Launched NCIS‘ Mark Harmon Into TV History
Mark Harmon has worn many hats throughout his long and successful acting career, but for millions of television viewers, he’ll always be Leroy Jethro Gibbs — the no-nonsense special agent with a heart of gold on NCIS. But few fans realize that before he led the Major Case Response Team, Harmon’s future as Gibbs was secured by a brief but unforgettable four-episode guest arc on another iconic TV series: The West Wing.
In fact, without The West Wing, there’s a good chance Harmon never would have become Gibbs at all.
Mark Harmon’s Role on The West Wing Changed Everything
Back in 2002, Harmon guest-starred as Secret Service Agent Simon Donovan on The West Wing during its third season. His mission? Protecting Press Secretary C.J. Cregg (played by Allison Janney) from a stalker. What followed wasn’t just another Secret Service storyline — it was a short, emotional, and powerful character arc that struck a chord with audiences and critics alike.
Donovan was cool, composed, and competent — a man of few words, but deep emotional complexity. His subtle flirtation with C.J. developed into a tender connection, culminating in a romantic kiss just as his assignment ended. Tragically, in a moment that shocked fans, Donovan was killed during a robbery before that budding romance could go any further.
Despite only appearing in four episodes, Harmon’s portrayal earned him an Emmy nomination for Outstanding Guest Actor in a Drama Series — and caught the attention of someone whose decision would change TV history.
One Performance, One Vision, and One Perfect Fit
Among those watching Harmon’s performance closely was Donald P. Bellisario, creator of shows like JAG and Quantum Leap — and, at the time, a man developing a new crime procedural that would eventually become NCIS. Bellisario saw something in Harmon as Donovan that others hadn’t noticed before.
“What I saw was a very controlled presence, a quiet strength,” Bellisario told Entertainment Weekly in 2006. “That’s what I was looking for. Leroy is Mark’s kind of guy. Mark has that jock mentality — you tough it out no matter how tough it is.”
Despite Harmon being best known as People’s 1986 “Sexiest Man Alive,” he hadn’t been seriously considered for such a grounded, stoic role. But those West Wing episodes reshaped Bellisario’s perception of Harmon entirely — and set the wheels in motion for what would become a 19-season tenure as Special Agent Gibbs.
The Audition That Changed NCIS Forever
Though Harmon left a strong impression, getting him into the lead role of Gibbs wasn’t a foregone conclusion. Other big names were being tossed around — including Harrison Ford, Alec Baldwin, Scott Glenn, and Andrew McCarthy. But NCIS casting director Susan Bluestein had someone specific in mind.
She’d worked with Harmon in 1991 and knew he had “the gravitas” for the role. After a meeting between Harmon and Bellisario, CBS execs were convinced. Charles Floyd Johnson, an executive producer on NCIS, later said Harmon’s screen presence helped reshape the show’s tone completely.
“Mark Harmon just made a big impression,” Johnson recalled. “They started testing it, and the first half-hour tested so well that Les Moonves said, ‘Why don’t we just make it all investigation?’” That decision helped define NCIS’ identity as the lean, focused investigative procedural fans came to love.
Behind-the-Scenes Tension That Almost Ended It All
Despite the early success, tensions behind the scenes started to simmer. By 2007, just a few seasons into NCIS, Harmon and Bellisario found themselves at odds. Reports suggested Harmon grew frustrated with Bellisario’s allegedly chaotic management style — including last-minute script changes and long, unpredictable work hours.
“Script pages get faxed to the set at the last minute,” an insider claimed at the time. “Mark is tired of dealing with the huge impact that makes on his life. He doesn’t have time for his family or anything when he’s working hours like that.”
Harmon eventually issued an ultimatum: change the way the show is run, or he’d walk away.
CBS sided with their leading man. Bellisario was quietly removed from day-to-day operations, and NCIS moved forward under new showrunner Shane Brennan. The result? A show that would not only continue — but thrive — for nearly two decades.
Legacy of a Role That Almost Didn’t Happen
It’s hard to imagine NCIS without Mark Harmon’s Gibbs — the strong but empathetic leader, the coffee-loving rule enforcer, the man who didn’t even lock his front door. But that defining performance wouldn’t exist if not for his short-lived character on The West Wing.
In many ways, Agent Simon Donovan was Gibbs in an early form: emotionally restrained but fiercely loyal, with a moral compass that ran deep. It was a spark that ignited the fire — and gave viewers one of the most enduring characters in TV history.
Now, even as NCIS continues with new spinoffs and a legacy that spans global franchises, the story of how Gibbs was born remains a reminder of how the right role, at the right time, can shape a career — and redefine a genre.
