Educated at Harrow School, where he was in the cricket XI in 1857, and Christ Church, Oxford, Stanhope studied law, being called to the bar at the Inner Temple in 1865.

When the Conservatives returned to the power, Stanhope became vice-president of the Committee of Council on Education, with a seat in the cabinet, and almost immediately thereafter President of the Board of Trade.

As War Secretary, Stanhope fought for reform against the reactionary high officers – most notably the Duke of Cambridge, the Commander in Chief, and Sir Garnet Wolseley, the Adjutant-General.

In spite of his own inexperience in military affairs and this formidable opposition, Stanhope achieved a fair amount, although it was his Liberal successor, Henry Campbell-Bannerman, who managed to push Cambridge into retirement.

In December 1893, Stanhope died suddenly of a heart attack, aged 53 whilst visiting his brother at the family estate of Chevening.