Gary Campbell went to Winchester College. In 1952, at the
age of 18 years old, he was commissioned in the service of the 1st King's
Dragoon Guards.
He gained the rank of Captain between 1954 and 1963 in the
North Irish Horse (Territorial Army.) He was a director of Henry Campbell
& Company Ltd between 1957 - 1972 and a chairman of Henry
Campbell Group Ltd between 1972 and 1981.