Kenny represented Ireland at the 2019 European Athletics U23 Championships in the 20 kilometres walk and finished in ninth place with a personal best time of 1:25:43. He again represented Ireland at the 2021 European Athletics U23 Championships in the 20 kilometres walk and won a silver medal with a time of 1:25:50. This was Ireland's ninth medal at the European Athletics U23 Championships, and first-ever racewalking medal.