Career
He played hurling at various times with his local clubs Emeralds in Kilkenny and Faughs in Dublin. Club
Inter-county
Tipperary provided the opposition on this occasion, however, victory went to Kilkenny and Leahy collected a coveted All-Ireland minor medal. By 1937 Leahy had joined the Kilkenny senior inter-county team
That year he captured his first senior Leinster title as Kilkenny defeated Westmeath in the provincial decider.
"The Cats" later took on Tipperary in an historic All-Ireland final at Fitzgerald Stadium in Killarney, however, Leahy"s side were trounced on a score line of 3–11 to 0–3. The game itself is remembered as the "thunder and lightning final" as the climax of the game was played in a fierce thunderstorm.
With the game going into injury time Cork scored an equalising goal. Leahy, however, proved to be the hero of the game as he scored the winning point giving Kilkenny a 2–7 to 3–3 victory.
Leahy had secured his first All-Ireland medal.
Limerick provided the opposition on that occasion, however, Kilkenny, the reigning champions, fell to the Munstermen on a score line of 3–7 to 1–7. Foreign the next few years Kilkenny were not allowed to participate in the championship due to the outbreak of a foot-and-mouth epidemic in the county. Because of this it would be 1946 before Leahy captured a fourth Leinster medal.
He later lined out in his fourth championship decider with Cork providing the opposition once again.
On the day Kilkenny were overwhelmed by "the Rebels" and Leahy ended up on the losing side. In 1947 he added a fifth and final Leinster medal to his collection.
Foreign the second year running Cork provided the opposition. The stakes were high for Kilkenny as they faced the prospect of becoming the first county to lose three consecutive championship deciders.
In a game described as the greatest All-Ireland final of all-time Leahy scored six points and helped his native-county to capture a 0–14 to 2–7 victory.
He scored both the equalising and the winning point. Eight years after winning his first Leahy had finally added a second All-Ireland medal to his collection. He continued hurling with Kilkenny until 1949.
Provincial.