You remember the boat, right? That massive wooden skeleton taking up half of a suburban basement, built by hand, plank by painstaking plank. It was the perfect metaphor for Leroy Jethro Gibbs. Methodical. Stubborn. Built for the long haul. When we talk about Mark Harmon on NCIS, we aren't just talking about a lead actor; we are talking about the guy who basically held the CBS primetime schedule together for nearly two decades. Honestly, most fans thought he’d stay until the lights literally went out on the set.
But then he left.
It’s been over four years since Gibbs decided to stay in Alaska, trading the high-stakes world of federal investigations for the quiet rhythm of fly fishing in the wilderness. People still search for "why he left" like there’s some hidden scandal buried under the floorboards of the NCIS headquarters. There isn't. Truthfully, the reality of his exit—and his surprising 2024 and 2025 moves—is way more interesting than the gossip.
Why Mark Harmon Left the Main Stage
The departure of Leroy Jethro Gibbs in Season 19, Episode 4, "Great Wide Open," wasn't a snap decision. It was a slow burn. If you’ve been following the behind-the-scenes reporting, executive producer Charles Floyd Johnson admitted that Harmon actually started dropping hints about wanting to step away as early as Season 15 or 16. That’s years of keeping the engine running while eyeing the exit.
Why? Fatigue. Plain and simple.
Imagine showing up to work at 6:30 a.m. five days a week for 18 years. Harmon has spoken openly about the "22-hour days" they pulled during the show’s early years. By the time he hit 70, the man wanted to see his wife, Pam Dawber, and their kids. He didn't want to be the "linchpin" anymore. He’d done his time.
The Myth of the "Bad Blood"
There’s always a subset of the internet convinced that Harmon left because of a feud. They point to the 2018 tension with Pauley Perrette (Abby Sciuto). While that was a very real, documented situation involving a dog on set and some serious workplace friction, it didn't drive him out. He stayed for three more seasons after she left.
The real reason he finally walked? He felt the character had reached a natural conclusion. Gibbs had been through the ringer: he’d lost his family, been shot multiple times, survived explosions, and gone to prison. Ending up in Alaska, finding "a sense of peace" he hadn't felt since his first wife Shannon died, was the only honest ending left for him.
The Ratings Gamble: NCIS Without Its Leader
When the news broke that Harmon was leaving, the industry doom-and-gloom was palpable. How do you keep a procedural alive when the guy on the poster is gone?
People expected the ratings to crater.
They didn't.
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Sure, the show isn't pulling the 20 million viewers it saw during its Season 10 peak, but it consistently stayed in the top ten. Gary Cole stepped in as Alden Parker—not as a "new Gibbs," but as a different kind of leader. It worked because the producers realized you can't replace an icon; you can only change the vibe of the room.
The 2024 Pivot: NCIS: Origins and the Return of the Voice
If you thought Mark Harmon was done with the franchise, you haven't been paying attention. In late 2024, the "Gibbs-verse" expanded in a way nobody saw coming with NCIS: Origins.
This isn't just another spinoff. It’s a prequel set in 1991, starring Austin Stowell as a young, grieving Gibbs just starting his career at Camp Pendleton. But here’s the kicker: Harmon is all over this show.
- Executive Producer: He and his son, Sean Harmon, are the driving forces behind the camera.
- Narrator: That gravelly voice you hear bookending the episodes? That’s Harmon, reflecting on his past.
- The Cameo: In the series premiere, we actually see the "present-day" Gibbs in Alaska, writing in a journal by a fire.
It turns out Mark Harmon on NCIS never actually ended; it just evolved into a mentorship role. He was heavily involved in casting Stowell, essentially passing the badge to a younger actor to keep the legacy alive while he enjoys the semi-retirement he earned.
The Big 2025 Crossover: "Gibbs is No Longer Alone"
The biggest news for fans in the last year was the massive crossover event that aired in November 2025. It was a Veterans Day special that linked NCIS: Origins with the flagship series.
For the first time in years, Harmon appeared on screen in a substantive way. The storyline involved a cold case from the '90s that young Gibbs investigated, which suddenly became relevant to the current D.C. team.
The showrunners, Gina Lucita Monreal and David J. North, teased something that sent the fanbase into a frenzy: "Gibbs is no longer alone." In that special, we saw a glimpse of his life in Alaska that suggested he might have found a companion or a new "family" of sorts. It provided the closure fans had been begging for since 2021.
What’s Next for Mark Harmon in 2026?
Harmon isn't just sitting on a porch. He’s recently become a New York Times bestselling author. His "Ghosts of..." series, co-written with real-life former NCIS agent Leon Carroll Jr., explores the true history of naval intelligence. The third book, Ghosts of Sicily, is slated for a spring 2026 release.
He’s also busy with the 2025 Freaky Friday sequel, reprising his role as Ryan alongside Jamie Lee Curtis. It seems the "retirement" was really just a career pivot into projects that don't require 14-hour days on a soundstage in Santa Clarita.
Actionable Insights for Fans
If you're looking to catch up or dive deeper into the world of Mark Harmon and the NCIS legacy, here is how you should navigate it:
- Watch the "Great Wide Open" Arc: If you haven't seen the first four episodes of Season 19, do it. It’s the most graceful exit of a TV lead in recent memory.
- Don't Skip Origins: Even if you aren't a fan of prequels, listen to the narration. It adds a layer of "future" Gibbs that we never got in the original series.
- Read the Books: If you like the procedural aspect of the show, Harmon’s non-fiction books (Ghosts of Honolulu, Ghosts of Panama) give you the "real" version of the agency.
- The Crossover Habit: Keep an eye on the flagship show during sweeps weeks (November and February). Even if he isn't a series regular, Harmon’s role as Executive Producer means he’s much more likely to pop up for "special events" than a full-time return.
The era of Gibbs leading the bullpens every Tuesday night might be over, but the character—and the man who built him—remains the heartbeat of the entire franchise. Mark Harmon didn't leave NCIS; he just moved to the back of the boat to make sure it stays on course.