In 1951, he entered the British government's Foreign Service, later transferring to the Diplomatic Service, and held posts in Egypt (1951), Cyprus (1952–53), Beirut (1953–56), Djakarta (1958–61), and Nairobi (1963–64).
He is the son of Arthur Ponsonby, 11th Earl of Bessborough, and his wife Patricia Minnigerode, daughter of Col. Fitzhugh Lee Minnigerode.
Eileen Myles | Ponsonby | Ponsonby, New Zealand | Alannah Myles | William Ponsonby, 1st Baron Ponsonby | Frederick Ponsonby, 6th Earl of Bessborough | William Ponsonby | Vere Ponsonby, 9th Earl of Bessborough | Nate Myles | Myles Standish | Myles Horton | Frederick Ponsonby, 10th Earl of Bessborough | Frederick Ponsonby | Myles Coverdale | Myles Brand | Conor Myles John O'Brien, 18th Baron Inchiquin | William Ponsonby (general) | The name of this cafe, ''Dorothy's Sister'', in Ponsonby, New Zealand | Sir Charles Ponsonby, 1st Baronet | Ponsonby Ponies | Myles Shevlin | Myles Pollard | Myles Burnyeat | James Myles Hogge | E. Myles Standish | Bernard Ponsonby | Arthur Ponsonby, 11th Earl of Bessborough | William Ponsonby, 2nd Earl of Bessborough | William Ponsonby, 1st Baron de Mauley | Rupert Ponsonby, 7th Baron de Mauley |
He died on 5 April 2002 and was succeeded by his eldest son Myles Ponsonby, 12th Earl of Bessborough