Born on 18 November 1902, into an Anglo-Irish aristocratic family with its roots in Ulster and County Durham, he was the second child and only son of the 7th Marquess of Londonderry and his wife, the Honourable Edith Helen Chaplin.

[2] He was known formally by his courtesy title, Viscount Castlereagh, before he inherited the Marquessate, and as Robin by close friends and family throughout his life.

He worked as honorary attaché to the British Embassy in Rome and as a director of Londonderry Collieries, the family's coal mining company.

Lord Londonderry was an accomplished public speaker and, before succeeding his father as Marquess in 1949, was the Unionist Member of Parliament for Down in the House of Commons of the United Kingdom from 1931 to 1945.

He was buried alongside his wife at Wynyard Park and both were later re-interred in the Londonderry family vault at St Mary's Church, Longnewton, County Durham.