By this stage Mullins was carving out a reputation for himself as a midfielder of note on the Dublin senior team. In 1974 he played in his first Leinster final in that grade. Archrivals Meath set out to stop 'the Dubs' claiming a first provincial title since 1965. A new look Dublin under the stewardship of Kevin Heffernan made no mistake in securing a 1–14 to 1–9 victory. It was Mullins's first Leinster winners' medal in the senior grade. Dublin later surprisingly defeated All-Ireland title-holders Cork in the semi-final, thus booking a place in the All-Ireland final against Galway. The men from the west, who had been beaten in two of the previous three championship deciders, took a 1–4 to 0–5 lead at half-time, however, the real turning point of the game came in the 52nd minute. Galway were awarded a penalty which Liam Sammon stepped up to take. Goalkeeper Paddy Cullen made no mistake and saved the shot. 'The Dub's' later went on to take the lead as Galway collapsed. A 0–14 to 1–6 score line resulted in a first All-Ireland winners' medal for Mullins and a first for Dublin in eleven years.