Educated at Eton College he was the only son of Charles Stewart Henry Vane-Tempest-Stewart, 7th Marquess of Londonderry and Edith Helen Chaplin.
He worked as honorary attaché to the British Embassy in Rome and as a director of Londonderry Collieries, the family's coal mining company. A keen football fan, he was first a director, and then later chairman of Arsenal Football Club from 1939 to 1946.
Known formally by his courtesy title Viscount Castlereagh and as Robin by friends and family, he was an accomplished public speaker and was Unionist MP for County Down in the British House of Commons between 1931 and 1945. He succeeded his father as Marquess of Londonderry in 1949.
Lord Londonderry was a celebrated host and practical joker, apparently once decorating the Christmas tree at Wynyard with condoms to startle a visiting cleric. He was also an attentive husband and devoted father to his children, entertaining them with stories and tales for hours on end. Also regarded as slightly eccentric, on one occasion Lord Londonderry had taken to his bed after a few drinks too many, when Mrs Billy Graham, wife of the evangelist, came to call. Although informed that His Lordship was "indisposed", Mrs Graham insisted upon immediate admission to his bedroom, having "come all the way on Billy's account". She was duly announced. Lord Londonderry threw aside the bed-sheets and shouted, "Get in.
But he had an awkward and distant relationship with his parents, especially his father. The two men took opposite sympathies during industrial disputes over the family coal mines and most notably during the general strike in 1926. When he was married to Romaine, a brewer's daughter, his family viewed the union with disdain. It was a very happy marriage by all accounts, but tragedy struck when Lady Londonderry died from cancer and Lord Londonderry plunged into depression and alcoholism.
"Daddy changed, literally overnight, into a complete drunk," she (Lady Annabel Goldsmith) remembers. "It was awful. He would collapse while making speeches to the cricket club, that kind of thing. He was on the bottle night and day.
Lord Londonderry died from liver failure on 17 October 1955 aged 52. He was buried alongside his wife at Wynyard Park and both were later reinterred in the Londonderry family vault at St. Mary's Church, Long Newton, County Durham.