John Costello

John started kickboxing at just 15 years old. At first, it was about learning how to defend himself… but over time it became something much deeper. Fighting became his way of expressing who he truly is. His introduction to MMA came from his dad, who once showed him the fight between Conor McGregor and José Aldo. The knockout. The lights. The belt. In that moment, watching it all unfold, John made a decision — this was what he wanted to do. From that point on, he kept stepping into the ring. Full-contact fights. Light-contact matches. Different opponents, different nights, but always the same test — walking forward, facing someone across from him, and proving to himself that he belonged there. He spent years training beside fighters who went on to win Irish titles, watching them raise their belts after hard battles. John wanted that moment too. He wanted to know what it felt like to reach the top. When his chance finally came and he fought for the Irish title, he lost. That loss showed John something important about this sport — how cruel it can be. After all the training, the sacrifices, and the years of work, everything can come down to one fight. But instead of breaking him, it lit a fire in him. Now John isn’t just chasing another belt. He’s chasing something bigger. He wants to go further than he ever imagined and prove that the loss that once hurt him became the moment that pushed him to the next level. And on April 25th, John steps back into the cage at Rumble Fighting Championship in Dublin… ready to show exactly how far he’s willing to go.