Dermot de Trafford was born at Marylebone in London, but grew up at the Loder Dower House, Cowfold, Sussex, which had been rented by his parents in 1936.
In 1938, he returned to England to study Modern Languages at Harrow School for four years, while there he won the school Steeplechase, breaking the school record, he also won the school prizes for French and German in 1942.