In 1744 and 1745 he saw further service on the Rhine, and he succeeded his father as 2nd duc de Broglie on the old duke's death in 1745.

[1] During the Seven Years' War, he served successively under Louis Charles César Le Tellier, duc d'Estrées, Charles de Rohan, prince de Soubise, and Contades, being present at all the battles from Hastenbeck onwards.

After the war, he fell into disgrace and was not recalled to active employment until 1778, when he was given command of the troops designed to operate against Great Britain, when France intervened on the Thirteen Colonies' side during the American war of independence.

He played a prominent part in the French Revolution, which he opposed with determination;[1] he commanded troops at Versailles in July 1789 and briefly served as Louis XVI's minister of war before fleeing France.

[citation needed] After his emigration, the duc de Broglie commanded the Army of the Princes for a short time (1792).