By 1974 Mac Curtain was a key member of the Cork minor hurling team. That year he won a Munster medal at that level before winning a second in succession in 1975. That same year he won an All-Ireland medal at minor level. In 1976 Mac Curtain had graduated onto the Cork under-21 team. That year he captured a Munster title at that level, before adding an All-Ireland medal to his collection. He won a second Munster under-21 title in 1977.