[1] She was the only child of James Ogilvie-Grant, 11th Earl of Seafield and the New Zealand heiress Mary Elizabeth Nina Townend (1876–1962).

[5][6] Her paternal grandparents were Francis William Ogilvie-Grant, 10th Earl of Seafield and the former Anne Trevor Corry Evans.

[7][8] Her father was killed in action on 12 November 1915 in France during World War I and Nina succeeded, suo jure, to the earldom of Seafield in the Peerage of Scotland.

Her uncle, Trevor Ogilvie-Grant, succeeded to the barony of Strathspey in the Peerage of the United Kingdom, and as Chief of the Clan Grant.

[2] On 2 January 1930, Lady Seafield's engagement was announced to Derek Herbert Studley-Herbert (1907–1960),[3] son of John Tatchell Studley and Beatrice de Chair.