One could argue that no single living person has done more to shape the rules and officiating of mixed martial arts than John McCarthy, the man who began his career as an MMA referee all the way back at UFC 2 in 1994.
One could also argue — as McCarthy himself would — that he had no idea what he was getting himself into back then, and might have reconsidered if he had.
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The first fight he refereed ended in less than 30 seconds. The second was only slightly longer than that.
“I go, ‘This is easy!’” McCarthy told a room full of referees, judges and commission officials at the 2026 Combat Sports Officials Summit in Las Vegas last month. “And from that moment, my life was a living hell.”
What he means is, there were some bumps in the road. Obstacles, you might say. Mistakes from which everyone must learn and grow. You set up a cage and organize some fights around the promise that there will be (almost) no rules, and then something happens that makes everyone think, ‘Well, actually maybe there should be a rule about that.’
Like how there was a time when no one in the UFC thought twice about letting fighters grab and cling to the chainlink fence of the cage. Then, McCarthy said, “Jerry Bohlander grabbed it so hard he bent the metal.”
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Next thing you know, the UFC had a rule against grabbing the fence. It’s still there today, along with a bunch of others that arose through a process of trial and error. After UFC 14 in 1997, for instance, McCarthy and other officials sat down and created 18 new rules. This gradual and sometimes painful process is how the modern version of MMA took shape — and McCarthy was there for it all. Through both his advocacy and his example, he formed the basis for how MMA should be officiated.
It’s a little strange for him now, at age 63, to look back on his place in the history of this sport. He initially accepted a role as referee for UFC 2 mostly as a favor to Rorion Gracie, whom he met through his own martial arts training. (Fun bit of trivia: Many people mistakenly think McCarthy began refereeing at UFC 1. In fact, he was present at the event, but he stuck close to Gracie with a gun concealed on his person, just in case family squabbles among the Gracie clan caused trouble.)
The instructions he was first given as a referee were simple: Don’t stop the fight until someone taps out or gets knocked unconscious. This is actually how he came to be hired for that second event. A referee named João Barreto disobeyed those instructions when he stopped a fight at UFC 1 after seeing blood and teeth sprayed across the canvas, so Gracie went looking for a replacement.
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According to McCarthy, he didn’t think those instructions were practical or smart. If he was going to referee, he told Gracie, he needed to be able to stop a fight once one of the fighters could no longer intelligently defend himself. Gracie resisted for a while.
Finally, McCarthy said, Gracie told him: OK, you can stop a fight if … whatever you said. And so it began. Rules. Guidelines. The vague shape of an actual sport forming. The process was, according to McCarthy, a “real pain in the ass.” But he believed in it, so he kept at it.
That was a few decades ago. He never thought this would be his life. Certainly not this long, or to this extent. Now there’s a whole generation of referees and other officials who’ve come up under his guidance, seeking out his advice. He’s happy to give it. He sees it as his primary way to contribute to the future of the sport at this point, doling out wisdom and warnings in that gruff big brother way he has, where it almost feels like he’s bullying you in a weirdly positive way.
According to longtime commentator and Uncrowned contributor Sean Wheelock, who helped organize this summit, McCarthy is the kind of person who, when you meet him, turns out to be “exactly who you want him to be.”
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McCarthy will gladly admit that he’s a person of strong opinions, never one to sit back quietly and watch others screw up. That helps explain why he’s stuck around so long in this sport, and also why he’s been such an important part of shaping it. As much of a pain as it might have been to fight against the current for so long with this sport, he didn’t have it in him to just give in and float downstream.
“I have a big mouth and it’s gotten me in a lot of trouble,” McCarthy said. “Throughout my time in the sport, I’ve pissed a lot of people off and that’s OK. I accept it. I accept that I’m not going to make everyone happy. I accept that not everyone’s going to like me, and I’m OK with that. But I would rather be honest and tell you, ‘Hey, this is my opinion and this is why.’ And if you don’t like it, that’s OK.”
Not unlike the fighters who stick around in this sport across multiple eras, McCarthy has lived many lives in MMA. From those wild early days to the growing pains of the modern era, all the way to a later period that came with difficult questions about how to manage his own physical decline, McCarthy has had to repeatedly reassess his role in MMA.
The biggest change for him came after a neck injury suffered on the mats about a decade ago.
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“I got hurt,” McCarthy said. “I got hurt bad. I got paralyzed. … It got to the point where I couldn’t lift my arm. … I couldn’t put my backpack, even though that’s all I had, into the upper tray of an airplane.
“I couldn’t take a potato chip and lift it to my mouth. So that was a concern. I was like, ‘S***, I’m not safe to go in there and do this job.’”
Sept. 9, 1994: John McCarthy has been there from the very beginning.
(Zuffa LLC via Getty Images)
When he realized he needed to step away was after UFC 217 in 2017, McCarthy said. He was working a title fight between Rose Namajunas and Joanna Jedrzejczyk, but when he went to stop the bout he realized his physical limitations were impacting how he did it.
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“In the older days, I would [have] just grabbed [Namajunas], pick her up away from [Jedrzejczyk], and stop the fight,” McCarthy said. “And I realized at that moment, I’m not sure I can pick her up.
“In my mind, I looked at it and went, ‘I can’t do this. I’m going to end up being the cause of someone getting hurt, because I’m not 100%.’”
Around this time, McCarthy got offered a job doing on-air commentary for Bellator broadcasts. It was a fine job, one he never felt entirely comfortable in, McCarthy said, but it wasn’t the same as officiating. As a ref, he reminded the attendees of the officials summit, you have a team. You have the other refs, the judges and the athletic commission officials, a community of people to support and help and guide you.
When he took the commentary gig, McCarthy said, his old team was gone. “You have no idea how much you miss it until it’s gone,” he added.
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In 2025, McCarthy got back in the cage as a referee. Neck surgery helped — first a disc replacement, then a fusion, making him the rare person to get both. His schedule isn’t nearly as packed these days, and he’s fine with that. What means more to him, he said, are these opportunities to help the next generation of officials.
Some of them — guys like Chris Leben and Frank Trigg — he first got to know when they were fighters. He watched them make a difficult transition from that life to this one, learning all new ways to be a part of the sport. Some of the people he’s mentored are mentors themselves now. It’s a satisfying feeling, and one he never expected when he first said yes to this gig.
“I’ll tell you, I got a text from one of these [referees],” McCarthy said. “I’m not going to say who, but I got a text from him today where he did fights yesterday and said, ‘Hey man, I want you to know that in my head, I was repeating the words that you told me the last time that we worked together.’
“And I was just like, ‘Dude, you know how good that makes me feel?’ I mean, that’s like hitting a home run. That’s like me having a great fight where everything goes right. The fact that, you know what, he went out and he used that little bit that I gave him and now he’s able to put that into his toolbox and make the right decision on a fight and feel good about it? Dude, there’s nothing better for me.”
