Mark Harmon Was Gibbs in 418 NCIS Episodes, and He’s Not Done Yet

The short answer is 418.

Mark Harmon played Leroy Jethro Gibbs in 418 episodes of NCIS, from “Yankee White” on September 23, 2003 to “Great Wide Open” on October 11, 2021, and his credits list him in every single one. Count the other shows Gibbs has walked into and the total climbs past 420. As of this week, it’s climbing again.

Here is how it breaks down:

• NCIS: 418 episodes (2003 to 2021)
• JAG: 2 episodes (April 2003)
• NCIS: New Orleans: 4 episodes (2014 to 2018)
• NCIS: Origins: 3 on-screen appearances so far (2024, 2025 and October 2026), plus his narration of every episode
• Total on screen so far: 427, give or take how you count the two-part Origins pilot

Where Gibbs started: two episodes of JAG

Gibbs didn’t begin on NCIS. He first showed up in April 2003 in a two-part episode of JAG, “Ice Queen” and “Meltdown,” which doubled as the pitch for a brand-new show. By September, the pitch had become a series, and Harmon was its lead.

It ran with him in charge for 18 seasons, which is a long time to live inside one character.

Why you’ll see 435 online

If you’ve searched this before, you probably landed on 435. It’s all over the internet, and it’s even on Harmon’s Wikipedia filmography. It isn’t a typo, but it isn’t an appearance count either.

Harmon left the cast four episodes into Season 19, but he stayed in the opening credits for the rest of the season). Season 19 ended with the show’s 435th episode. Do the math (418 episodes with Gibbs, plus the 17 he’s credited in but absent from) and you land on 435. So the number is real, but it counts billing, and Gibbs wasn’t in those last 17 episodes.

What about a voice cameo in Family Guy? Harmon has a credit there too, in the 2012 episode “Tom Tucker: The Man and His Dream.” It’s a fun footnote, but it’s a spoof broadcast and it isn’t counted above.

The goodbye in Alaska

Gibbs’s last scene as a regular came in “Great Wide Open,” which aired on a Monday night in October 2021. Gibbs and McGee chase a contract killer all the way to Naktok Bay, Alaska. When the case is over and the FBI agent hunting Gibbs lets him go, he tells McGee he isn’t coming home.

“I’m not going back, Tim,” he says. He explains that he hasn’t felt this kind of peace since his wife Shannon and daughter Kelly died, and he isn’t ready to let it go.

There was no big funeral and no team farewell. Gibbs just settled in on a fishing boat, which suited the character, and Harmon himself later said he thought the path the character took was honest. The show also left the door open. Showrunner Steven D. Binder put it this way: “Never count Leroy Jethro Gibbs out.”

Harmon never really stepped away from the show, either. He remains an executive producer, so his name stayed on the show well after he left the cast.

Four visits to New Orleans

In between, Gibbs made four guest appearances on NCIS: New Orleans. Two were phone and video calls: “Breaking Brig” in 2014, when Dwayne Pride needed help with a redacted file, and the 2018 Season 5 premiere “See You Soon,” when Gibbs gave LaSalle some advice while Pride fought for his life. The other two were the crossover hours “Sister City, Part II” (January 5, 2016) and “Pandora’s Box, Part II” (February 14, 2017).

Gibbs never really left

Then came NCIS: Origins, the prequel about Gibbs as a young agent in the early 1990s. Harmon doesn’t play the young Gibbs (that’s Austin Stowell), but he narrates every episode as the older man looking back. When the series launched in 2024, he also showed up for a brief appearance in the pilot, still in Alaska.

Then, on Veterans Day 2025, he came back in person for the NCIS and Origins crossover, “Funny How Time Slips Away.” It was a quiet scene at his cabin with a dog, but it was Gibbs again, and it was his first time back on screen since the pilot. “It seemed like a good time to check in with him,” Harmon said when the return was announced.

This week the check-in got bigger. In the Origins Season 3 premiere on October 6, a gunman shoots present-day Gibbs in the chest at his cabin, and he gets back up, loads his sniper rifle and says, “Time to get to work.” Harmon is slated to appear in all ten episodes this season. The number on this page will keep growing as the season goes on.

The flagship show has found its own way to nod to him, too. In May 2026, a sniper shot from 4,500 feet and a dinner of salmon “fresh from Alaska” strongly hinted that Gibbs had helped avenge Director Vance. Gibbs never appeared on camera, so that one doesn’t count toward the total. Binder said a return had to be “worthy” of the character, and protecting his family was about as worthy as it gets.

Will Gibbs come back to NCIS?

For the moment, Gibbs lives in Alaska and in the prequel, and the main show has been keeping him offscreen. Binder has explained why: he wants Gibbs to stay larger than life, and he’d rather not picture him “living in an apartment in Anchorage.” When Harmon was asked last year whether he’d appear again, he gave a typically Gibbs answer, “I don’t know… So we’ll see.”

That isn’t a no. After years of fans asking, the old Gibbs is on screen again, which is more than most people expected in 2021. If you want to follow how that return came together, we covered the November 2025 crossover and the man behind the character earlier.

Beyond the badge

Harmon’s other long-running project is a book. Ghosts of Honolulu, co-written with retired NCIS agent and longtime show adviser Leon Carroll Jr., came out in November 2023. It is a true story about Douglas Wada, the only Japanese American agent in naval intelligence, and Takeo Yoshikawa, a Japanese spy sent to Pearl Harbor in the years before the attack. Harmon said he wanted to tell the real history behind what became NCIS.

That’s the tally for now: 418 episodes of the show, 427 across the whole Gibbs universe, and one stubborn Marine who keeps finding a reason to step back into the frame.