La Galissonière had family connections to New France as his mother was a sister of Michel Bégon, the intendant from 1712 to 1726. He also married Marie-Catherine-Antoinette de Lauzon, a relative of Jean de Lauzon, the Governor of New France from 1651 to 1657.
La Galissonière was a naval commander who reluctantly accepted the position of Governor due to military necessity. He appears to have been well liked but was limited by resources to accomplish much that would distinguish himself during his stay in New France. He did send Céloron de Blainville to extend France's trading posts and François Picquet to convert the Indians in the Detroit area and the Ohio valley in order to out-flank the British American colonies.
His strength was as an administrator and diplomat. In recognition of his service in New France, he was promoted to the rank of rear-admiral, despite never having been tested militarily. Eventually, he was charged with heading the Dépôt de la Marine.
In 1756, La Galissonière supported the invasion of Menorca (historically called "Minorca" by the British) and was engaged in combat for three hours by Admiral John Byng. La Galissonière was extremely cautious and was rewarded by a British withdrawal. Byng was court-martialed and executed. The modest naval victory over the British was lauded in France to the point that the king was said to be preparing a marshal's baton for La Galissonière's return. However, the naval commander died from illness, aged 63, prior to their meeting.
La Galissonière is mentioned in a Fort Saint-Jean plaque erected by Historic Sites and Monuments Board of Canada 1926 at the Royal Military College Saint-Jean. "Constructed in 1743 by M. de Léry under orders from Governor la Galissonnière. This post was for all the military expeditions towards Lake Champlain. In 31 August 1760, Commandant de Roquemaure had it blown up in accordance with orders from the Governor de Vaudreuil in order to prevent its falling into the hands of the English. Rebuilt by Governor Carleton, in 1773. During the same year, under the command of Major Charles Preston of the 26th Regiment, it withstood a 45 day siege by the American troops commanded by General Montgomery."