In form Crowley is English, a habitation name from an Old English term meaning "wood of the crows", and no doubt some of those in Ireland bearing the name derive from English stock. However, the vast majority are of Gaelic Irish extraction, with Crowley an anglicisation of O Cruadhlaoich, from cruadh and laoch, meaning "hardy" and "warrior". The Cruadhlaoch from whom the family take their name lived in the mid-11th century and was in fact one of the MacDermots of Moylurg in Connacht, Diarmuid an Cruadhlaoch, a son of Conchubhar son of Diarmuid, a quo the Mac Diarmuida Ruaidh, MacDermott Roe. Some time later, probably in the late thirteenth century, descendants of an Cruadhlaoch migrated from Connacht to Co. Cork, where they settled an area north of the Bandon river in the barony of East Carbery. A local tradition has it that they acquired their territory by marrying into the ruling family of the Coughlans, whom they then ousted. The townlands of Curraghcrowly East and West in this district record their presence. In any event, while the original Connacht branch of the family declined, descendants of the Cork family prospered and multiplied, in part no doubt due to their well-deserved and formidable reputation as fighters. Their dispossession in the confiscations of the seventeenth century was almost total, since they were prominent on the losing sides in all the major conflicts of the period. The vast majority of Irish Crowleys today are connected to the Cork branch, and that county is still home to most of them. In 1890 there were 161 births of the name, 116 of these in Co. Cork.
Nicholas Joseph Crowley (1819-1857) was a distinguished portrait painter.
.Eugene Crowley (1926 - ), from Ballineed, Co. Cork, was Commissioner of the Garda Siochana from 1988-1991.
Bob Crowley (1955 - ), from Cork, has an international reputation as a stage designer. He works with Britain?s National Theatre and Royal Shakespeare Company.