Studied in Dublin and in continental Europe before being apprenticed to Walter Doolin, eventually establishing the partnership Doolin, Butler and Donnelly before practising privately. Editor of The Irish Builder from 1899 and one of the principal commentators on architecture in Ireland for the next thirty years, Butler was a leading church architect. He also won the competition to design the University College Dublin (now National Concert Hall) building on Earlsfort Terrace and head of architecture in the college from 1924 to 1943. Another building in the Dublin area designed by Butler is the former Gorevans Department Store, a fine concrete building with its structure clearly expressed. President of the AAI (1906-7) and Fellow of the RIBA (1906). Held the Chair of Architecture at University College Dublin (1924-42).