Curran's performances at under-age levels brought him to the attentions of the Cork selectors at senior level. He made his senior championship debut in 2003, a year which saw Cork's players emerge from a bitter stand-off with the county board and reach the Munster final for the first time in three years. Waterford provided the opposition on that occasion as one of hurling's modern rivalries began in earnest. An exciting game resulted between the two teams; however, victory went to Cork by 3–16 to 3–12. It was Curran's first Munster winners' medal in the senior grade and it gave a signal that Cork were back. Cork were hot favourites going into the subsequent All-Ireland semi-final against Wexford, however, it was far from a walkover. In one of the most exciting games of the championship both sides finished level: Cork 2–20, Wexford 3–17. Both sides met again six days later with Cork making no mistake and taking the spoils on a score line of 3–17 to 2–7. This win set up an All-Ireland final meeting with Kilkenny. In another thrilling game of hurling both teams were level for much of the game, exchanging tit-for-tat scores. A Setanta Ó hAilpín goal steadied the Cork ship, however, a Martin Comerford goal five minutes from the end settled the game as Kilkenny went on to win by 1–14 to 1–11.