You probably know him as Demetri. The tall, sarcastic, "confident introvert" who went from being a punching bag to a legitimate karate badass in Cobra Kai. But before he was trading kicks with Hawk or obsessing over MIT, Gianni DeCenzo was a child actor grinding in the Disney Channel ecosystem.
Most people don't even realize it, but Gianni DeCenzo Liv and Maddie is a real connection. It's not just a rumor. He wasn't a series regular, and he wasn't part of the main "Rooney" crew, which is why your brain probably didn't register him during those mid-2010s marathons.
He played Young Joey.
Yeah, the younger version of Joey Bragg’s character, Joey Rooney. It was a brief moment in the grand scheme of the show, but for DeCenzo, it was a pivotal piece of the puzzle that led to his Netflix stardom.
The "Young Joey" Role: What Actually Happened
Acting is a weird business. One day you’re doing a commercial for Subway, and the next, you're on the set of one of the biggest sitcoms for teens. Gianni DeCenzo’s appearance on Liv and Maddie happened during the height of the show's popularity.
In the episode "Flashback-A-Rooney" (Season 1, Episode 18), the plot dives into—you guessed it—the past. While Dove Cameron was busy playing two different versions of herself, Gianni was tasked with capturing the essence of Joey.
Honestly, it was perfect casting. Joey Rooney was known for being the quirky, slightly socially awkward brother who marched to the beat of his own drum. If you look at Gianni's performance as Demetri years later, you can see the seeds of that same energy.
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- He wore the signature Joey-style gear.
- He had to mimic Joey Bragg’s specific mannerisms.
- He even got to meet the "older" Joey on set.
Gianni has mentioned in interviews that meeting Joey Bragg was a highlight. Apparently, they even took a photo together where they made the exact same face. It’s one of those "if you know, you know" trivia facts that makes rewatching the early seasons of Liv and Maddie feel like an Easter egg hunt.
Why Nobody Remembers Him in the Show
It’s simple. He was a kid.
When Gianni filmed Liv and Maddie, he was significantly younger and hadn't hit that massive growth spurt that makes him stand out in the Cobra Kai dojo. Plus, the show was so focused on the "Liv vs. Maddie" dynamic and the twins' individual subplots that guest stars—especially those playing younger versions of the main cast—tended to blend into the background.
Also, let’s be real. In the Disney Channel world, guest spots are a dime a dozen. You’ll find future Oscar nominees and Marvel stars hiding in the background of Hannah Montana or Wizards of Waverly Place if you look hard enough. Gianni was just another talented kid in the machine.
Transitioning From Disney to Cobra Kai
The jump from a "Disney kid" to a Netflix lead isn't always easy. Some actors get stuck in that "bright colors and canned laughter" style of acting. Gianni, however, credits his time on shows like Liv and Maddie and Coop & Cami Ask the World for giving him the confidence to be "silly and bold."
Basically, Disney taught him how to commit to a bit.
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When he auditioned for Cobra Kai, he brought that comedic timing with him. Demetri could have easily been an annoying character. Instead, Gianni made him relatable. He took the "nerd" trope and gave it teeth.
"Disney really treats their young actors very well... being silly and bold on Disney Channel gave me the confidence to not be afraid to make mistakes." — Gianni DeCenzo on his early career.
Facts vs. Fiction: Sorting Through the Rumors
Because Gianni has become so popular lately, some fans have started "Mandela Effect-ing" his career. I've seen TikToks claiming he was a recurring villain or that he played one of Parker’s friends.
Let's set the record straight:
- Was he a regular? No. Just a guest spot.
- Did he share scenes with Dove Cameron? Sorta. He walked past her in a hallway during filming, but they didn't really have "acting" scenes together since he was playing a version of her brother in a different time period.
- Is he still in touch with the cast? He mostly speaks fondly of Joey Bragg, as they shared the character.
How to Find the Episode
If you want to see "Baby Demetri" in action, you have to head over to Disney+.
Search for Liv and Maddie, go to Season 1, and look for Episode 18, "Flashback-A-Rooney." It’s a fun watch, mostly because you get to see how much he’s changed. He’s got the same expressive eyes, but the "karate kid" we know now is nowhere to be found yet.
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He was just a kid in a hoodie trying to make people laugh.
What This Means for His Career Now
Gianni DeCenzo isn't just "the guy from the karate show" anymore. He's a seasoned vet with over 15 years in the industry. Starting at eight years old with commercials and bit parts on The Middle and Liv and Maddie gave him a foundation that a lot of overnight TikTok stars just don't have.
He understands the grind.
As Cobra Kai wraps up its final seasons, Gianni is positioned as one of the breakout stars to watch. He’s already expressed interest in writing and producing, which makes sense given how much he’s absorbed from being on sets since he was a literal child.
If you’re a fan of his work, the best way to support him is to keep an eye on his upcoming projects outside the "Miyagi-verse." He’s proven he can do the Disney sitcom thing and the high-stakes action-drama thing.
Next Steps for Fans:
- Check out his guest appearances on NCIS and NCIS: Los Angeles for a more "serious" side of his acting.
- Follow his social media where he often talks about his Krav Maga training—something he actually uses to do his own stunts.
- Rewatch that Liv and Maddie episode just to see how far the "Young Joey" has come.