• Marshal of France François de Gaston, Chevalier de Lévis, 1719

   

In 1756, the Marquis de Vaudreuil was informed that King Louis XV of France was sending the Marquis de Montcalm to take over the French forces in North America, with Lévis as second in command. Vaudreuil wrote back to the king stating that there was no need to send another general, as Vaudreuil disliked the tactics of most "municipal" French generals. When Montcalm arrived in spite of Vaudreuil's protest, the two men developed a dislike for each other. Lévis diplomatically cultivated good relations with both men, and managed to avoid getting dragged into the feuds between the two leaders.

Lévis led the vanguard of the French expedition to Fort William Henry in 1757, and established the siege prior to Montcalm's arrival.

French planning for the 1758 campaign in the French and Indian War continued the disputes between Vaudreuil and Montcalm. Vaudreuil prevailed, and Montcalm was sent to Fort Carillon to defend against an expected British attack, and Levis was initially slated to lead an expedition to the western forts, leading about 500 French metropolitan troops and then a large force of seasoned French Canadian militia. Vaudreuil, however, had second thoughts, and dispatched Levis and his metropolitan troops to support Montcalm at Carillon. Lévis arrived at Carillon on the evening of July 7, as a British army was arriving before the fort. The next day, in a stroke of good fortune for the defenders, the 16,000 strong British army under the command of General James Abercrombie decided to frontally attack the French defenses manned by about 4,000 men, without the benefit of artillery support. In the Battle of Carillon, the British were decisively defeated, with Lévis leading the defense on the French right flank.

When the forces of James Murray arrived to begin the Siege of Quebec, Lévis participated in the early defenses, including the Battle of Beauport. He was then sent to organize the defense of Montreal, and was not present when Quebec fell. Following Montcalm's death at the Battle of the Plains of Abraham, Lévis was appointed commander of French forces in North America. Wintering at Montreal, Lévis managed to rally his troops and train them for a spring offensive aimed at recapturing Quebec in 1760. Marching downstream with the first breaking of the ice, Lévis met the forces of James Murray at the Battle of Sainte - Foy, where Lévis' army won a striking victory, forcing Murray to retreat behind Quebec's walls. The lack of artillery and siege equipment precluded any assault on the fortifications of Quebec and Lévis held back, awaiting reinforcements from Europe. With the arrival of a British squadron, Lévis was obliged to retreat to Montreal, where Vaudreuil eventually surrendered New France to Amherst's army, which had advanced down the Saint Lawrence River that summer, in early September. Lévis, unhappy with the terms of capitulation, which did not include traditional "honors of war", burned regimental colors rather than turning them over to the British.

Levis returned to France on parole, and was released for service in Europe by William Pitt. He served in the German campaigns of 1762, and retired from active military service when the war ended in 1763 with the Peace of Paris. He was appointed governor of Artois in 1765. He was promoted to Marshal of France in 1783, and was raised to the inheritable title Duc de Lévis in 1784.

He died in 1787 in Arras, France, and was succeeded as duke of Lévis by his son Pierre - Marc - Gaston, who escaped to England during the French Revolution. His widow and three daughters were sent to the guillotine during the French Revolution.