Tallis first played hurling at juvenile and underage levels with the Lisdowney club, while also playing as a schoolboy with Coláiste Mhuire in Johnstown. He progressed to adult level with his club and was top scorer when Lisdowney beat Thomastown to win the Kilkenny IHC title in 2020. Tallis first appeared on the inter-county scene as goalkeeper on the Kilkenny minor hurling team that lost the 2019 All-Ireland minor final to Galway. He progressed to the under-20 team and was again in goal when Kilkenny beat Limerick in the 2022 All-Ireland under-20 final.