He was appointed Grand Chamberlain of France in 1644, shortly after the Guises were permitted to return from their exile in Florence. Louis XIV having returned the confiscated lands of Joyeuse, and the title "Joyeuse", to the once disgraced Guises, upon his majority in 1647 Louis de Lorraine was granted the title Duke of Joyeuse, the duchy of his maternal ancestors.
As Colonel General of the light cavalry, he served as a volunteer at the siege of Gravelines in 1644, and in two other campaigns. ("His company of mounted guards and their trappings were the finest possible", commented a newsletter of the time.) He died in Paris from a wound in his right arm, received on 22 April 1654, while charging the enemy near Arras. He was buried at Joinville near his paternal ancestors.
He married on 3 November 1649, in Toulon, Marie Françoise de Valois (d. 1696), daughter of Louis Emmanuel, Duke of Angoulême, who succeeded her father in 1653. Mentally unstable (imbécile), she was confined, by her mother, to the chateau of Ecouen or at the Hotel d'Angouleme. A few years after their marriage, Marie was sent to the abbey of Essey. They had two children:
| Duke of Joyeuse
| Count of Eu|
| Duke of Angoulême
with Marie Françoise