Although the original territory of the O'Tooles lay in Co. Kildare, in the twelfth century they were displaced by the invading Normans, and migrated into the adjoining county of Wicklow, where the area they controlled was roughly identical to the old diocese of Glendalough, with the centre of their power in the region around the Glen of Imaal. Despite the proximity of Dublin, the centre of English rule in Ireland, the O'Tooles maintained a fierce independence and, together with their neighbours and occasional allies the O'Byrnes, were a source of great fear to the inhabitants of Dublin and the Pale for almost four centuries. It was only in the seventeenth century, with the final and general collapse of Gaelic power, that the O'Tooles were "pacified", as the English put it.
Unlike most of the other Gaelic aristocracy, however, the line of the O'Tooles survived intact; there were two branches, of Powerscourt and Castle Kevin, both in Wicklow. Descendants of the former are living in Wicklow and in the U.S. The representatives of the latter have lived in France for many generations.
The most famous bearer of the name is undoubtedly St. Laurence O'Toole (1132-1180), a member of the leading O'Toole family who became abbot of the monastery of Glendalough at the age of 25, and was chosen by the people and clergy as first Archbishop of Dublin in 1162. He subsequently led the resistance and negotiation with the Norman invaders.
From Captain Lauence O?Toole of Wexford, an officer in the Irish Brigade of the French army are descended the family of Count O?Toole of Limoges.
Peter O?Toole (1932 - ) was born in Connemara and brought up in England. He has received 7 Oscar nominations for his film roles. The best known of these is probably in the title role of Lawrence of Arabia.(1962)