By this stage he had already joined the Kilkenny senior hurling team, making his debut in an Oireachtas game in 1966. The following year he was a non-playing substitute as Kilkenny captured both Leinster and All-Ireland honours, however, it wasn't until 1969 that Cummins found a regular place on the team at midfield. That year he missed 'the Cats' Leinster final triumph over Offaly, however, he later lined out in his first All-Ireland final appearance. Cork faced Kilkenny in that game and revenge for the defeat in 1966 was foremost in the minds of the Kilkenny team. For a while it looked as if the Leesiders would triumph over their great rivals once again, however, five points from Kilkenny in the last seven minutes gave the Noresiders the victory and gave Cummins a first All-Ireland medal.