[citation needed] At the age of eight, d'Angeac began his military career as a guard at Port-Dauphin, Nova Scotia (now Englishtown) on Île Royale.
He was promoted to captain in 1747, and accompanied Île Royale's garrison to Quebec before returning to Louisbourg in 1749 upon its reoccupation by France.
[2] With the signing of the 1763 Treaty of Paris, the islands of Saint-Pierre and Miquelon became a new French colony, replacing Louisbourg as France's sedentary fishery base and deep-sea fishing fleet refuge.
When d’Angeac was appointed governor, Sir Charles Douglas delayed d'Angeac while Captain James Cook worked quickly to complete his survey of Saint-Pierre and Miquelon.
With his recommendation, he was succeeded by his nephew, Charles Gabriel Sébastien, Baron de l'Espérance (1725, Louisbourg;[11] died 1791).