At club level he played with Éire Óg and was a two-time All-Ireland Championship winner with the Kilkenny senior hurling team.
[1][2] From 1939 onward Mulcahy was a regular on the senior team and struck up a forward partnership with Seánie O'Brien and Jim Langton.
[3] Mulcahy played in his fifth All-Ireland final in 1950, lining out at full-forward against Tipperary, but Kilkenny were beaten by a point.
Mulcahy was the holder of four county senior championship medals with Éire Óg and had the distinction of winning county medals in four grades - minor, junior intermediate and senior - in the space of five years.
He died aged 43 on 26 April 1962 after suffering from colon cancer and was survived by his wife and three sons.