A professional soldier, he was a regimental commander during the Thirty Years Wars, and was later appointed commissary general of French forces in Germany.

He returned to France after reaching peace settlements with the Mohawk and the other Iroquois nations, and was appointed commandant at Dunkirk, and later governor of the Château Trompette in Bordeaux.

He was appointed commissary general of the French army in Germany, and represented France in negotiations with Sweden and the Elector of Bavaria that led to the 1647 Truce of Ulm.

After receiving numerous pleas for help, Louis XIV took several steps to ensure the survival of New France, including sending professional soldiers.

[3] In November 1663, Tracy was commissioned by Louis XIV as "lieutenant général throughout the length and breadth of the continental countries under our authority situated in South and North America."

He was assigned two tasks: remove the Dutch from Cayenne (a former French colony in Guiana), and end the threat of the Iroquois to New France.

After anchoring off Percé, Tracy and the soldiers that had accompanied him to the West Indies transferred to smaller ships and disembarked at Quebec on 30 June, 11 days after the first four companies of the Carignan-Salières had arrived from France.

To avoid overcrowding in Quebec, Tracy sent the Carignan-Salières companies to build three forts along the Richelieu River, the main route used by the Mohawk in their raids on French settlements.

For many years the Mohawk had raided French settlements, and had disrupted the flow of beaver pelts to Montreal by blockading the Ottawa and St. Lawrence Rivers.

The expedition was within two days march of Mohawk territory when they encountered a delegation led by the warrior known as the Flemish Bastard who was bringing the unharmed French prisoners back to Fort Sainte Anne.

600 French soldiers, 600 Canadien volunteers, and 100 Algonquin and Wendat warriors rendezvoused at Fort Sainte Anne at the end of September.

[4] Upon his return to Quebec, Tracy had a Mohawk prisoner hanged and sent the Flemish Bastard and two Oneida back to their people with his terms for peace.

A peace settlement was finally reached in July when several hostage families arrived at Quebec, and requested Jesuit missionaries be sent to the Mohawk and Oneida homelands.

[3] Marie de l'Incarnation wrote that Tracy had "won over everyone by his good works and by the great examples of virtue and religion which he has given the whole country.