Born at Tandragee Castle, County Armagh, Ireland, Lord Mandeville was the son of the 9th Duke of Manchester, by his marriage to Helena, the daughter of Eugene Zimmerman, of the United States. After they divorced in 1931, Helena married secondly, in 1937, the Earl of Kintore.
Mandeville was educated at the Royal Naval College, Osborne, and at Dartmouth.
From Dartmouth, Lord Mandeville joined the Royal Navy. He held the rank of Commander when he retired from the service in 1930.
On 5 May 1927 he married firstly, at Kimbolton Castle, Huntingdonshire, Nell Vere Stead (died 2 September 1966), daughter of Sydney Vere Stead of Melbourne, Australia, by whom he had two sons. On 7 February 1969 he married secondly, and without further issue, Elizabeth Fullerton, daughter of Samuel Clyde Fullerton of Miami, Oklahoma, USA. She had formerly been married to William Willard Crocker.
During the Second World War, Mandeville was posted to Ceylon, and in 1940 he was appointed an Officer of the Order of the British Empire. After the end of the War he gave up living in England, moving to Kenya in 1946. There, he farmed an estate of 10,000 acres. He succeeded to the Dukedom of Manchester on his father's death in 1947.
During the 1950s the Duke sold both the family seat, Kimbolton Castle, along with most of its contents, and Tandragee Castle. By the 1960s, he had also sold most of the other landed estates in the United Kingdom which had come to him.
At the time of his death in 1977 he was still listed in Who's Who as living at Kapsirowa, Hoey's Bridge, Kenya, but he died in London, after running through most of his inherited wealth.
His elder son, Sidney Arthur Robin George Drogo Montagu (1929–1985) succeeded him to the family titles. He died without issue, so his brother Angus Charles Drogo Montagu (1938–2002), became the 12th Duke.1902–1947: Viscount Mandeville
1947–1977: His Grace The Duke of Manchester