du Blé was born at Chalon-sur-Saône. His appearance was described as tall and ruddy, with a huge wig and a hat pulled down over his eyes. He tended to hide his military orders and decorations under a plain, tightly-buttoned coat. Second heir of Louis Chalon du Blé, marquis of Uxelles (who died in 1658 at the siege of Gravelines), and of Marie Le Bailleul (1626–1712), Nicolas Chalon du Blé was a protégé of Camille le Tellier de Louvois.