In 1746, he sailed on the famous and ill-fated Duc d'Anville Expedition, intended to retake Louisbourg (now in Nova Scotia) from the English in King George's War, the North American portion of the War of the Austrian Succession.

As Governor General, de la Jonquière was considered to be a good administrator, if not the bravest of men in the political and economic upheavals of the time.

But the opposite was true of his naval career, where his twenty-nine campaigns and nine combats demonstrated that he was a man of great courage.

Historians believe that de la Jonquière personally profited from the French Canadian monopoly of the fur trade with American Indians and First Nations at the time.

Given his administrative position, he should have abstained from that type of commercial activity and conflict of interest.