The Galway Kickboxing Club member beat Stelyan Avramidi of Kazakhstan to claim the gold medal at -71kg by unanimous decision at the Citywest Hotel and Conference Centre in Dublin. Brosnan said: “I can’t even describe what it feels like to be world champion,
“I don’t think it has fully sunk in yet.”
His father and coach Denis added: “He’s been training since he could walk. I’m very proud of him.”
Ireland won six medals at the finals. Three of those were silver in semi-contact kickboxing.
Ireland’s former world champion Robbie McMenamy lost out to Zsolt Moradi of Hungary in the final seconds of the -79kg final while Des Leonard lost his final in extra time.
Ireland’s youngest competitor, Ashley St Mart (16), was bitterly disappointed after losing a tough final against Laszlo Varga of Hungary while Niall McDermott and Shauna Bannon claimed bronze medals in the -67kg full contact and -60kg semi contact respectively.