McCarthy's performances in the other grades of hurling brought him to the attentions of the Cork senior selectors. He made his debut in the 2002 National Hurling League with Cork reaching the final of that competition. McCarthy lined out at wing-forward in that game against Kilkenny. A close match developed, however, 'the Cats' secured a narrow 2-15 to 2-14 victory. McCarthy later made his championship debut that year, however,Cork, showing little or no appetite for battle, were eliminated by Galway in the second round of the qualifiers that year.