At the Saint-Sulpice Seminary (Issy-les-Moulineaux) in Paris, after winning his doctorate at the Sorbonne, he was ordained to the priesthood in 1734, and became a Sulpician.
During King George's War (1744–1748) between France and Britain, the Indian allies of these two powers came to arms.
Due to Picquet's influence, the Five Nations, hitherto allies of the British, remained neutral, while the others carried out several raids in New England or served as scouts for the French troops.
[1] It was during that period that Picquet made the decision to work with the Indians south of the Great Lakes for conversion and to ensure their loyalty to France.
In 1748 a commitment was made by Roland-Michel Barrin de La Galissonière, the Governor General of New France, to send Picquet to the Thousand Islands area for that purpose.
In 1758, with the Seven Years' War intensifying, a military commander was put in charge of that new aspect of the fort.