Begley first came to prominence on the inter-county scene as a member of the Limerick under-21 team. He won a Munster title at this level in 2000 before later collecting an All-Ireland Under-21 Hurling Championship medal following a victory over Galway. It was Limerick's first step towards three such titles in-a-row; however, Begley was over-age for the latter two victories. By this stage, he had joined the county senior team. Following the county's victory over Cork in the Munster Senior Hurling Championship in 2001, Limerick failed to win a game in the province until their 2007 Munster SHCsemi-final victory over Tipperary. This was achieved following a three-game saga; however, Begley's side later lost the Munster SHC final to Waterford. Limerick beat Waterford in the subsequent All-Ireland SHC semi-final, setting up an All-Ireland SHC final meeting with Kilkenny on 2 September 2007. While Begley scored a goal and won a penalty, his side lost by seven points to Kilkenny, on a scoreline of 2–19 to 1–15.