He was created count of Cagny (modern Crillon) and duke of Boufflers and named marshal of France.

He was famed for his excellent defensive leadership during the sieges of Namur and Lille, next to his conduct during the Battle of Malplaquet.

On 15 October 1688, he took the important fortress Mainz, the Aureum caput regni, with 20,000 soldiers, then he led a corps to the Sambre, and reinforced François Henri de Montmorency, Duke of Piney on the eve of the Battle of Fleurus (1690).

In 1708, when Lille was threatened with a siege by John Churchill, 1st Duke of Marlborough and Prince Eugène of Savoy, Boufflers was appointed to the command, and made a most gallant resistance of three months.

Here he displayed the highest skill, and after Villars was wounded he conducted the retreat of the French army without losing either cannon or prisoners.

Louis-François' daughter, Louise Antoinette Charlotte, married his cousin, Charles François de Boufflers.