One could argue that no living person has done more to shape the rules and refereeing of mixed martial arts than John McCarthy, who began his career as an MMA referee back in 1994 at UFC 2.
One could also argue that – like McCarthy himself – he had no idea what he was getting into at the time and might have reconsidered had he known.
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The first game he refereed ended in less than 30 seconds. The second one is just a little longer than that.
“I said, ‘That’s easy!'” McCarthy told a room full of referees, judges and commission officials at the 2026 Combat Sports Officials Summit in Las Vegas last month. “From that moment on, my life became a living hell.”
What he means is, there are some bumps in the road. There are obstacles, you might say. Mistakes that everyone must learn and grow from. You set up a cage, organize some fights around the promise of (almost) no rules, and then something happens that makes everyone think, “Well, actually maybe there should be a rule about that.”
Just like there was a time when no one in the UFC thought twice about letting a fighter grab and cling to the wire of the cage. Then, McCarthy said, “Jerry Boland grabbed it so hard that he bent the metal.”
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Next thing you know, the UFC has a rule against grabbing the fence. It still exists today, along with a few other products that came about through trial and error. For example, after UFC 14 in 1997, McCarthy and other officials sat down and created 18 new rules. This gradual, sometimes painful process was how modern mixed martial arts came to be—and McCarthy was involved every step of the way. Through his advocacy and example, he laid the foundation for how MMA should be refereed.
Now, at 63, he looks back on his place in the history of the sport with some oddity. He initially accepted the UFC 2 referee position primarily as a favor to Roryon Gracie, whom he met through his martial arts training. (Fun trivia: Many people mistakenly believe that McCarthy started refereeing at UFC 1. In fact, he was there, but he was stuck next to Gracie with a gun hidden on him in case a family feud between the Gracie family caused trouble.)
His initial instructions as referee were simple: Don’t stop play until someone is down or knocked unconscious. That’s actually why he was hired for the second event. A referee named João Barreto violated those instructions when he stopped the fight at UFC 1 after seeing blood and teeth sprayed on the canvas, so Gracie began looking for a replacement.
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According to McCarthy, he believed the instructions were not practical or sensible. He told Gracie that if he was going to be a referee, he would need to be able to stop a fight when one of the fighters could no longer defend themselves sensibly. Gracie resisted for a while.
Finally, McCarthy said, Gracie told him: Well, if… whatever you say, you can stop fighting. That’s how it all started. rule. guidelines. The blurry shape of actual motion is taking shape. McCarthy said the process was “really painful.” But he believed in it, so he kept at it.
That was decades ago. He never thought this would be his life. Of course it won’t be this long, or to this extent. An entire generation of referees and other officials now look to him for advice. He is happy to give. He sees this as his main way of contributing to the future of the sport right now, dishing out wisdom and warnings in his gruff big brother way that almost feels like he’s bullying you in a weirdly positive way.
Longtime commentator and “Uncrowned King” contributor Sean Wheelock, who helped organize the summit, said McCarthy is the kind of person who, when you meet him, you find “exactly who you want him to be.”
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McCarthy would readily admit that he was a man of strong opinions and was never one to sit back quietly and watch others screw up. This helps explain why he has stayed in the sport for so long, and why he played such an important role in shaping it. As painful as it might be to fight the current for so long in this sport, he didn’t have the ability to give in and swim downstream.
“I have a big mouth, and it gets me into a lot of trouble,” McCarthy said. “I’ve pissed off a lot of people throughout my time in this sport, and that’s OK. I accept it. I accept that I’m not going to make everyone happy. I accept that not everyone is going to like me, and I’m OK with that. But I’d rather be honest with you and say, ‘Hey, this is my opinion and this is why.’ If you don’t like it, that’s OK.”
Unlike boxers who have stuck with the sport across multiple eras, McCarthy has seen a lot of life in MMA. From his wild early days to his modern-day growing pains, and later faced with the dilemma of how to control his physical decline, McCarthy has had to repeatedly re-evaluate his role in MMA.
The biggest change for him came after a neck injury on the mat about a decade ago.
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“I was hurt,” McCarthy said. “I was seriously injured. I was paralyzed…I couldn’t lift my arms…I couldn’t put my backpack into the upper tray of the plane, even though I only had the backpack.”
“I couldn’t lift the chips to my mouth. So that was a problem. I was like, ‘S***, it’s not safe for me to go in and do this job.'”
September 9, 1994: John McCarthy has been there from the beginning.
(Zuffa LLC via Getty Images)
McCarthy said it was after UFC 217 in 2017 when he realized he needed to leave. He was in the middle of a title fight between Rose Namajunas and Joanna Jedrzejczyk, but when he stopped fighting, he realized his physical limitations were affecting the way he played.
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“Before, I would [have] just caught [Namajunas]pick her up and leave [Jedrzejczyk]and stopped fighting,” McCarthy said. “That’s when I realized, I wasn’t sure I could pick her up.
“In my mind, I looked at it and thought, ‘I can’t do this. I’m going to end up being the reason someone gets hurt because I’m not 100 percent.'”
Around this time, McCarthy got a job doing on-air commentary for Bellator Radio. McCarthy said it was a good job but he never felt completely comfortable, but it wasn’t the same as officiating. As a referee, he reminded attendees of the Official Summit that you have a team. You have other referees, referees and sports commission officials, a group of people to support, help and guide you.
McCarthy said his old team disappeared when he took the commentary job. “You don’t know how much you miss it until it’s gone,” he added.
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In 2025, McCarthy returned to the cage as a referee. Neck surgeries helped — first a disc replacement and then a fusion, making him the rare person to get both. His schedule isn’t as packed these days, but he doesn’t mind that. More important to him, he said, are these opportunities to help the next generation of officers.
Some of them — like Chris Leben and Frank Trigg — he first met when they were fighters. He watched them make the difficult transition from that life to this life, learning all the new ways to be a part of the sport. Some of the people he mentored are now mentors themselves. It’s a satisfying feeling, one he never expected when he first agreed to the gig.
“I’m telling you, I got a text from one of them [referees],” McCarthy said. “I won’t say who it was, but I got a text from him today and he played the game yesterday and said, ‘Hey, man, I want you to know that in my head, I’m repeating what you told me the last time we worked together. ‘
“I was like, ‘Man, you know how good this makes me feel?’ I mean, it’s like hitting a home run. It’s like I’m having a great fight and everything is going great. The fact that, you know, he went out and used a little bit of what I gave him and now he’s able to put it in his tool box and make good decisions in the fight and feel good about it? Man, there’s nothing like it for me.”
