Duffy was added to the Tipperary senior hurling team in advance of the 1923 Munster Championship.
[2] Although known as a right wing-back at club level, Duffy was selected at right wing-forward for the 1925 All-Ireland final against Galway.
[citation needed] Duffy was born in Rathcabbin, County Tipperary, the youngest of three children of John and Jane (née Nolan).
His father died when he was seven year old and, after completing his education at Rathcabbin N.S., he took over the running of the family farm from his uncle.
An opponent of the Anglo-Irish Treaty, he took the Republican side during the Civil War and was imprisoned at various times in Birr Castle, Templemore, Portlaoise and the Curragh.