Cummins began his juvenile and underage career as a hurler with Blackrock while also played Gaelic football with sister club St. Michael's. It was with the latter team that he enjoyed his first major success by winning the Cork MFC title as a 14-year old in 1965. He later won three successive Cork MHC titles with Blackrock.
By 1968, Cummins had joined both clubs' top adult teams and was part of the St. Michael's side that won the Cork IFC title a year later. He enjoyed his first success with the Blackrock senior hurling team when the club made a clean sweep of Cork SHC and Munster Club Championship in 1971, before later lining out at corner-forward when Blackrock beat Rathnure in the 1972 All-Ireland club final.[6] Cummins won a second All-Ireland club medal two years later when Blackrock once again beat Rathnure in the 1974 All-Ireland club final.[7]
Cummins was on and off the Cork panel over the following few seasons, but earned selection during a number of games during Cork's successful 1973-74 National League campaign. He became a first team regular during the 1975 Munster SHC and was at centre-forward for the defeat of Limerick in the final.[17] Cummins was again at centre-forward for the 2-21 to 4-11 defeat of Wexford in the 1976 All-Ireland final.[18]