In 1996 Cloonan joined the Athenry senior team. It was a successful debut year as he subsequently collected a championship medal following a 2–6 to 1–6 defeat of Carnmore. Cloonan missed the subsequent provincial decider, however, Athenry later reached the All-Ireland decider against Wolfe Tones. Nine points from Cloonan helped Athenry to a 0–14 to 1–8 victory. It was his first All-Ireland medal.
