In the period 1974 to 1979 John won three All Ireland medals in 1974, 1976 and 1977. John was a crucial figure in these years particularly in the 1976 All Ireland final against old rivals Kerry as John struck for the first goal to set Dublin on their way to victory. He proved to be a real thorn in Kerrys side as he was also fouled for the penalty which led to Dublins second goal. He repeated the dose against Kerry in the classic semi final of 1977 when he plundered Dublins first goal shortly after half time. In the final of 1977 John was part of a Dublin full forward line that amassed all but two of the teams two points in a tally of 5-12 against Armagh.
John was a Garda by profession based at Mountjoy and holds a unique record alongside Kerry's Aidan O'Mahony and Tom O'Sullivan within the force of being the only Gardaí to play in six successive All Ireland finals. He retired from the Garda Síochána in 2005.
Johns' son named James was a senior footballer with Dublin who won the All-Ireland Senior Football Championship on one occasion.