He was granted military leadership in 1688, during the Nine Years' War; he served as lieutenant general at the siege of Philippsburg, and was charged with holding the Place de Mayence fortress in Mainz, when the French army was forced to retreat.

He retained the favor of François-Michel le Tellier, Marquis de Louvois and Louis XIV of France, and was rewarded with the fief of Rougemont-le-Château (1696), and he received the baton of Marshal, in 1703.

He was one of the aristocratic architects of the polysynody system of government, and obtained the first presidency of the Council of Foreign Affairs, (1715–1718) when the regency of Philippe II began.

As president of the Council of Foreign Affairs, Blé tended to the popular, traditional French view of favoring Catholic Spain over Protestant Great Britain.

According to one source, the Regent even made Blé kiss the Treaty of the Triple Alliance, which allied France with Britain and the Dutch Republic against Spain.