He was a captain of cavalry in a regiment of Cardinal Mazarin. He served in the Thirty Years War taking part in the Siege of Lleida in 1644 and, the following year in the Battle of Nördlingen in which he was injured (his brother Charles III, Duke of Elbeuf, also served in this battle). A good military man, he later fought against Spain prior to the marriage between Louis XIV and Maria Teresa of Austria, which cemented peace between the two nations.