Before he was trading roundhouse kicks in a Valley dojo, Tanner Buchanan was dealing with a much different kind of pressure: the literal weight of the free world. Or at least, the weight of being the First Son.
You probably know him now as Robby Keene from Cobra Kai. But if you rewind the clock to 2016, a younger, shaggier-haired Buchanan was pacing the halls of a fictional White House. Playing Leo Kirkman in the ABC-turned-Netflix political drama Designated Survivor, he wasn't just another TV teenager. He was a central piece of a massive conspiracy puzzle.
The Leo Kirkman Era: More Than a Side Plot
Honestly, when Designated Survivor first dropped, everyone was obsessed with Kiefer Sutherland’s Tom Kirkman. Who wouldn't be? The guy survives a literal explosion and becomes President overnight. But the "First Family" dynamics were the secret sauce that made the show feel human.
Tanner Buchanan played Leo Kirkman as a kid who was, well, kinda pissed off. Imagine being sixteen and having your entire life uprooted because your dad—who wasn't even supposed to be that important—is suddenly the most powerful man on the planet.
Leo was rebellious. He was self-absorbed. He was basically every teenager you’ve ever met, but with Secret Service agents breathing down his neck.
One of the big plot points early on involved a paternity scandal. It was messy. People were whispering that Tom Kirkman wasn't Leo's biological father. This wasn't just "teen drama" filler; it was a move by political enemies to delegitimize the new administration. Buchanan had to play that vulnerability with a level of nuance most young actors struggle to hit. He wasn't just a brat; he was a kid realizing his parents might have secrets that could topple a government.
Why did he vanish from the show?
This is what most people get wrong or simply forget. If you watched the third season on Netflix, you might have noticed a Leo-sized hole in the West Wing.
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Basically, Buchanan’s career was blowing up.
While Designated Survivor was moving from ABC to Netflix for its final season, Buchanan landed the role of Robby Keene in Cobra Kai. Scheduling conflicts are a reality in Hollywood. Because he was a main lead in the Karate Kid spin-off, his time as Leo Kirkman had to be dialed back. In the show's world, Leo simply headed off to Stanford University.
It was a clean exit, but fans definitely missed the dynamic he had with his on-screen sister, Penny (played by Mckenna Grace).
Training in Secret: The Connection You Missed
Here is a wild bit of trivia: Tanner Buchanan actually started his martial arts journey while filming Designated Survivor.
Most people think he learned everything for Cobra Kai. Wrong. While he was in Toronto filming scenes for the Kirkman family, he spent about eight months training in Muay Thai. He was already a black belt in Shotokan karate-do from his childhood in Ohio, but he used his downtime on the political drama to level up his combat skills.
He even inherited "kali sticks" from his maternal grandfather, who was Filipino. He uses them for Escrima, a traditional Filipino martial art.
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So, while Leo Kirkman was busy being a moody student, the actor playing him was quietly becoming a lethal weapon. It’s funny to think that if a group of assassins had actually breached the White House in the show, Leo probably could have handled himself better than the Secret Service.
The "Designated Survivor" Legacy
Tanner wasn't just a guest star. He appeared in 28 episodes.
That’s a lot of screen time. It served as his bridge from being "the kid from Girl Meets World" to being a genuine leading man. You can see the evolution in his performance. In the pilot, he’s a bit one-note. By the time he’s dealing with the paternity test results and protecting his sister, he has this grounded, protective energy that he later brought to his role in Cobra Kai.
He also worked alongside some heavy hitters:
- Kiefer Sutherland: Who probably gave him a masterclass in "intense whispering."
- Natascha McElhone: Who played his mother, Alex Kirkman.
- Kal Penn: Who went from being a White House staffer in real life to playing one on TV.
Being around that kind of talent at age 17 is like going to the Harvard of acting.
What’s He Up To Now?
It’s 2026, and Buchanan isn't just "the kid from that one show" anymore. After Cobra Kai wrapped its massive run in 2025, he hasn't slowed down.
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He’s moved into voice acting with Star Wars: Visions, playing Prince Arluu. He’s also done the rom-com thing with He’s All That and the indie drama circuit with films like Anything. He even narrated an audiobook for The Great Gatsby. The guy has range.
And for the fans who love a good "workplace romance" story—yes, he is still with Mary Mouser. They met on the set of Cobra Kai (she played Samantha LaRusso), and their relationship has been a fan-favorite "ship" that actually became real.
Actionable Insights for Fans and Aspiring Actors
If you're looking to follow Buchanan's trajectory or just want to appreciate his work more, here is the breakdown of how he did it:
1. Diversify your skills early.
Buchanan didn't just act. He danced (tap and jazz), he played guitar in a death metal band called "Acidosis," and he kept up his martial arts. When the Cobra Kai audition came around, he didn't have to fake the athleticism. He lived it.
2. Don't snub the "Teen Roles."
Some actors feel "above" playing the rebellious son. Buchanan took the Leo Kirkman role and gave it layers. He treated a political thriller like a character study.
3. Loyalty matters.
Even after leaving Designated Survivor for bigger things, he’s always spoken highly of the cast. In an industry built on bridges, he doesn't burn them.
If you haven't revisited the early seasons of Designated Survivor lately, go back and watch Tanner Buchanan. You’ll see the seeds of a superstar being planted in the middle of a national crisis.
To truly understand Buchanan's range, your next step should be to watch the Season 1 episode "The Interrogation." Pay close attention to how he handles the scenes where the media is hounding him about his parents. It’s a masterclass in "internalized" acting—where everything is said through the eyes rather than the dialogue. After that, jump straight into a Season 1 episode of Cobra Kai to see how he transformed that same "loner" energy into physical aggression. It’s a fascinating evolution of a young actor finding his voice.