(1817–82). Arguably Ireland's greatest Gothic Revival architect, called the ‘Irish Pugin’. Dublin-born, he flourished during the impressive building-programme of the Irish RC Church after ‘Catholic Emancipation’ (1829), designing in a robust First and Second Pointed style, following the lead of Pugin and the Ecclesiologists in England.
He may have been in England during the early 1840s, but in 1846 work started on his Church of St Kevin, Glendalough, Co. Wicklow. In a severe First Pointed style, it was the first attempt by a native-born Irish architect to build a church on Ecclesiological principles. McCarthy was one of the three joint-secretaries of the Irish Ecclesiological Society, founded in 1849, and he published Suggestions on the Arrangement and Characteristics of Parish Churches (1851). In 1853 he was appointed Architect to the Armagh RC Cathedral in succession to Thomas Duff of Newry, Co. Down. Although the building was well advanced, McCarthy abandoned Duff's Perpendicular for Second Pointed in accordance with Ecclesiological preferences, added the two western steeples, omitted the crossing-tower, and increased the pitch of the roof. In the process he changed the character from English to French Gothic, reflecting his growing Irish Nationalism by adopting non-English exemplars, even though the stylistically earlier work on top of stylistically later architecture is visually absurd. He built many churches in Dublin (St Saviour's, Dominic Street, is the finest) and Co. Kerry, drawing on the great wealth of Irish ecclesiastical remains for the elements of his designs. Occasionally he made forays into Romanesque revival, as at the chapel, Glasnevin Cemetery, Dublin (finished 1878), and the Cathedral of the Assumption, Thurles, Co. Tipperary (1865–72), but most of his work is assured Continental Gothic, as at St Patrick's, Dungannon, Co. Tyrone (1870–6), the Chapel, Maynooth College, Co. Kildare (1875–1903), and St Macartan's Cathedral, Monaghan (1861–92).
From A Dictionary of Architecture and Landscape Architecture in Oxford Reference.