[citation needed] Heaslip also represented the Leinster inter-provincial team on a number of occasions, winning one Railway Cup medal.
Heaslip scored a hat-trick of goals in the home final defeat of Kerry, before claiming an All-Ireland Junior Championship medal after the 5-02 to 2-08 win over London.
Heaslip was retained on the Kilkenny panel for the 1957 Leinster Championship and made his debut on 30 June in a 1-11 to 2-08 semi-final draw with Dublin.
After returning to the starting fifteen for the 1959 Leinster Championship, Heaslip claimed a third successive provincial winners' medal, his second on the field of play, after the 2-09 to 1-11 victory over Dublin.
Injury ruled Heaslip out of the 1963 Leinster Championship, however, he claimed a fourth provincial winners' medal from the substitutes' bench after the 2-10 to 0-09 defeat of Dublin in the final.
On 1 September 1963, he was restored to the starting fifteen at right wing-forward when Kilkenny faced Waterford in the All-Ireland final for the fourth time in seven seasons.