Louis-Joseph de Montcalm-Gozon was born on February 28, 1712, at the Château de Candiac near Nîmes in southern France. He was the son of Louis-Daniel de Montcalm and Marie-Thérèse de Lauris, members of an old but financially constrained noble family. As the eldest surviving son, he inherited family responsibilities along with the expectation of military service. He received a classical education under private tutors, studying Latin, history, religion, and literature while also learning the manners and obligations of a provincial gentleman.

Montcalm entered the French Army in 1721 as an ensign in the Régiment d’Hainaut, although his youth meant that serious active service came later. He became a captain in 1729. In 1736 he married Angélique Louise Talon du Boulay, and their marriage produced numerous children, though several died young. His letters reveal strong attachment to his family and persistent concern over debts, estates, and the cost of maintaining noble status.

During the War of the Polish Succession, Montcalm served on the Rhine and gained early campaign experience. In the War of the Austrian Succession he fought in Bohemia and Italy. He was wounded at the Battle of Piacenza in 1746 and captured after the defeat at Assietta in 1747. These campaigns taught him siegecraft, conventional maneuver, and the personal hazards of command. He earned promotion through courage and competence, becoming colonel of the Régiment d’Auxerrois.

Between wars Montcalm returned to Candiac, managed family affairs, read widely, and sought further advancement. In 1756 he was promoted to maréchal de camp and appointed to command France’s regular troops in Canada. He crossed the Atlantic as an experienced European officer and cultivated nobleman, but with little direct knowledge of Canadian militia, Indigenous warfare, or the political authority of a colonial governor.