During the Second World War, Lord Rupert Nevill gained the rank of captain in the
Life Guards. He served as
aide-de-camp to Lieutenant-General
Sir Brian Horrocks during the allied advance in 1945 and continued as aide-de-camp after the war until 1947. Nevill served as Chairman of the
British Olympic Association from 1966 to 1977 and as its President from 1977 until his death in 1982, being succeeded in this role by
Anne, Princess Royal. He was President of the
British Show Jumping Association between 1973 and 1976. Nevill was also President of the Metropolitan Union of the
YMCA from 1956, a member of the World Council of the YMCA from 1956, vice-chairman of the National YMCA 1963-1966, and president from 1966. He was president of the East Grinstead and Uckfield branch of the
RSPCA. He was also an ardent defender of
fox hunting and member of the Eridge Hunt. In 1959, he resigned after a decision by the branch to offer a free service for gassing foxes by a qualified pest controller. He was a member of the Uckfield Rural District Council (1949–1967) and of
East Sussex County Council (1954–1967), a
Justice of the Peace of
Sussex from 1953, and a
Deputy Lieutenant of Sussex from 1960. He was
High Sheriff of Sussex for 1952–1953. He was a member of the Sussex St John's Council from 1952 and chairman from 1966. Nevill was treasurer to the
Prince Philip, Duke of Edinburgh from 1970 to 1982 and his
private secretary from 1976 to 1982. He was one of the godfathers of
Princess Margaret’s son
David Armstrong-Jones, 2nd Earl of Snowdon. ==Personal life==