Born in Aldershot on 9 November 1860, the only surviving son of Major-General St George Nugent and Emily Litton, Oliver Nugent came from a distinguished Southern unionist landowning family but grew up acutely aware of his Irish ancestry:
‘We are not really a N[orth] of Ireland family and as a matter of fact, the Nugents were for James and against William in the days when the North was founding itself. All our family associations lie in the midlands of Ireland and it is merely a geographical accident that we live inside Ulster.’
This inherent sense of belonging would colour his turbulent relationship with Ulster unionism during the Great War.
Related to the Lords Delvin of Westmeath, the Nugents formed part of a long-established tradition of Old English landholding in County Cavan. This dynastic link remained an object of inordinate pride, so much so that the family ensured that each birth was recorded and connected via a direct genealogical line to Christopher, 14th Baron Delvin (1544–1602). The Nugent family estate was relatively untouched during the Ulster Plantation, and although the Cromwellian land confiscations drastically reduced their holding, they managed to evade the rigours of the Penal Laws by converting to the established church following the Williamite wars. By the second half of the eighteenth century they had become committed Anglicans and a fully integrated part of the Protestant Ascendancy.