Blanchfield first played hurling at juvenile and underage levels with Bennettsbridge before eventually joining the club's senior team. He also played as a schoolboy with St. Kieran's College and won consecutive All-Ireland titles in 2018 and 2019. Blanchfield first appeared on the inter-county scene as a member of the Kilkenny under-20 hurling team that won the Leinster U20HC title in 2019. He was added to the senior team two years later and, after winning National League and Leinster Championship titles, lined out in the 2022 All-Ireland final defeat by Limerick