Born in Ballyduff, County Kerry, Costelloe first arrived on the inter-county scene when he first linked up with the Kerry minor team in both football and hurling before later joining the under-21 hurling side.
Born in Ballyduff, County Kerry, Costelloe first played competitive hurling in his youth. He arrived on the inter-county scene when he first linked up with the Kerry minor team in both football and hurling before later joining the under-21 hurling side.