He was mentioned in despatches in 1943. From 1949-1951 he was in command 2nd Frigate Flotilla, and then was Naval Attache in Rome 1951 to 1953. After spending 1953 to 1955 at the Admiralty he became Commanding Officer of HMS Glasgow in 1955 and 1956. His last posting was as Chief of Staff Mediterranean (1957–1959).
In 1959 Bonham-Carter joined the Household of the Duke of Edinburgh as Treasurer to the Duke of Edinburgh. In 1970 he was appointed Private Secretary, and retired from both positions at the end of that year. In 1961 during a Royal visit to Nepal he was credited with a share a tiger kill with Sir Michael Adeane in a royal tiger hunt. The tiger shooting role had fallen to him after the Queen had declined, the Duke of Edinburgh had been unable to shoot due to having his trigger finger in a splint and the then Foreign Secretary Alec Douglas-Home had missed twice.
He is the grandfather of actor Crispin Bonham-Carter.