He was introduced as a 56th-minute substitute for Geoff Brennan in the 2-15 to 2-11 defeat. Walsh was eligible for the minor grade again the following year and established himself as a regular member of the starting fifteen. On 4 July 2010, he won a second successive Leinster Championship medal following a 1-20 to 0-10 defeat of Dublin in the final. On 5 September, Walsh was at centre-forward when Galway faced Clare in the All-Ireland final. He was substituted by Paul Holden in the 39th minute but collected a winners' medal following the 2-10 to 0-14 victory. Two years later Walsh was a key member of the Kilkenny under-21 team. He won his sole Leinster medal that year following a 4-24 to 1-13 trouncing of Laois. Kilkenny later faced Clare in the All-Ireland decider. A powerful second-half display, in which they outscored Kilkenny 1-10 to 0-4, saw Clare take their second ever All-Ireland under-21 crown. On 7 June 2011, Walsh made his first appearance for the Kilkenny under-21 team. After starting the game on the bench, he was introduced as a substitute in the 1-16 to 2-12 defeat by Wexford in the Leinster Championship. On 11 July 2012, Walsh won a Leinster Championship medal from centre-forward after scoring six points in Kilkenny's 4-24 to 1-13 defeat of Laois in the final. On 15 September, he was again at centre-forward for Kilkenny's 2-17 to 2-11 defeat by Clare in the All-Ireland final. Walsh was moved from the forwards to the right wing-back position for the 2013 Leinster Championship. He made his last appearance in the under-21 grade on 11 July 2013 when Kilkenny suffered a 1-21 to 0-21 defeat by Wexford in the Leinster final. Walsh was added to the Kilkenny senior team as a substitute for their National Hurling League semi-final against Clare on 22 April 2012. He was again included amongst the substitutes for the final against Cork on 6 May. Walsh remained in the bench but collected a winners' medal following the 3-21 to 0-16 victory. He failed to be included on the Kilkenny panel for the Leinster Championship. On 18 March 2013, Walsh made his first competitive appearance at senior level.