He succeeded his father as Duke of Alençon and Count of Perche as a minor in 1415, after the latter's death at the Battle of Agincourt.

"[3] Before his capture at Verneuil, he had married in 1424, at the Chateau de Blois, Joan, daughter of Charles, Duke of Orléans, and Isabella of Valois,[4] but she died in Angers in 1432, having had no children.

In April 1429, not long after his release, the Duke heard about Joan of Arc, who had come to King Charles VII at Chinon, promising to liberate France from the English, asking that he send her with an army to lift the Siege of Orléans.

After she raised the siege alongside Jean de Dunois and La Hire, among others, Alençon arrived as the official commander of the French army and played a major role in the liberation of the rest of the Loire Valley.

[6]) Shortly after participating in the "rehabilitation trial" of Joan of Arc in 1456 where he provided extensive testimony,[7] John was arrested by Jean de Dunois and imprisoned at Aigues-Mortes.