‘NCIS’ Cast Credits Mark Harmon for Leading Show with ‘Integrity’ over 450 Episodes

Can you believe it? 450 episodes! Our beloved NCIS just hit a television milestone that most shows only dream of. It's the kind of number that makes you stop and think, "Wow, that's a lot of cases solved!" To celebrate this incredible achievement, the folks at ET got exclusive access to the set, chatting with the cast as they toasted to nearly two decades of crime-solving drama. And while the team looks a bit different these days, the echoes of its origins, especially the influence of longtime star Mark Harmon, are still deeply felt.

Honoring the Foundation: "A Big Tribute to Mark Harmon"

Even though Mark Harmon's Leroy Jethro Gibbs hung up his NCIS hat early in season 19, his presence looms large. Wilmer Valderrama, who burst onto the scene as Nick Torres back in season 14, didn't mince words when talking about the show's foundation.

"What NCIS has done beautifully... we're here on the shoulders of so many incredible actors that were here before us," Valderrama shared with ET. He reflected on the show's power, noting how it launched careers and became a staple for fans and the industry alike.

But he made a special point to acknowledge the man who started it all:

"It is also a big tribute to Mark Harmon, who led this beautifully for hundreds of episodes and was able to keep this boat with the integrity and the value set that it still performs today."

Valderrama beautifully summed up the balance: Harmon built the ship, and now the current crew is keeping it fresh and exciting. "There's a recipe of things that have to really go right in order for you to get to 450," he admitted. It's a team effort, spanning years and generations of cast members.

New Faces, Same Magic: The Team Today

Katrina Law, who joined as the sharp Jessica Knight towards the end of season 18, echoed the sentiment of being part of something special.

"NCIS, the entire franchise, has managed to capture magic in a bottle," Law said. "And the fact that the show at 450 episodes is still the No. 1 show on television is just a testimony to the juggernaut that is NCIS."

You can feel the chemistry building with the current team. Law noted how they're hitting their stride: "You're really starting to see us gel... As actors personally, we're getting to know each other. So the freedom to have fun on set is becoming boundless at this point." Fans are definitely noticing the Torres and Knight partnership solidify, and who isn't curious about that budding workplace connection between Knight and Jimmy Palmer?

And the 450th episode itself? Sounds like classic NCIS with a personal twist. Diona Reasonover (our brilliant Kasie Hines since season 15) teased a look into Alden Parker's (Gary Cole) past with the arrival of his dad, promising some potential "headbutting" – we love family drama mixed with our investigations!

What's the Secret Sauce? It's All About Family (and Maybe Not Jinxing It)

Hitting 450 episodes puts NCIS in rarefied air, chasing legends like Gunsmoke and Law & Order: SVU. So, what is the secret to keeping viewers hooked for two decades?

Brian Dietzen, who’s been with us as the lovable Jimmy Palmer since the very beginning (season 1!), has a theory:

"I think that throughout the different iterations of this show, the thing that's remained constant is the characters... they've kind of served to form a family, and I think that their interactions are what keep people coming back."

He nailed it, didn't he? It's less about the "case of the week" and more about how our team reacts, supports each other, and grows through it all. Diona Reasonover wholeheartedly agreed, saying the audience falls in love with the characters just like she did.

Sean Murray, another Day 1 veteran as Timothy McGee, had a more superstitious (and hilarious) take: "You don't talk about the no-hitter!" Fair enough, McGee! But he later expressed pure gratitude: "It's incredible... To be a part of something like this is just, it's incredible."

Gary Cole, the newest team lead as Alden Parker, kept it short and sweet: "I'm saying it's working. We don't know. But we're still standing here."

Eyes on the Horizon: Chasing Records and Making History?

With season 21 already locked in, the cast is feeling optimistic, even playful, about the future. Can they catch Gunsmoke's staggering 635 episodes?

"We're coming for you, Gunsmoke!" quipped Cole.

"I think we got it in us for a while," added Law, believing the fans will stick around for the ride.

Valderrama pointed out the unique position NCIS is in. Few, if any, currently airing scripted shows have a realistic shot at those kinds of numbers. Its continued success, even after 450 episodes, suggests anything is possible.

It’s a pretty wild thought. As Gary Cole mused, "It's really unlikely that a fictional scripted series will ever be in this situation again."

450 episodes down. Who knows how many more to go? One thing's for sure: the NCIS team, past and present, has created something truly special, built on integrity and kept alive by character, chemistry, and a whole lot of heart. Here's to the stories already told, and the many more we hope are yet to come!