In 1407, Jean's father, Louis I, Duke of Orléans was assassinated. Eight years later, his half-brother, Charles, Duke of Orléans was captured at the Battle of Agincourt and remained a prisoner of the English for twenty-five years. This left Jean the only adult male to represent the house of Orléans. He was Knight of the Order of the Porcupine.
Jean joined the civil war in France in the time of Charles VI on the side of the Armagnacs, and was captured by the Burgundians in 1418. Released in 1420, he entered the service of the Dauphin Charles, fighting in the Hundred Years' War against English forces. The future count of Dunois led the French defenses at the siege of Orléans. Together with Joan of Arc he relieved the siege. He joined her on the campaigns of 1429 and remained active after her death.
Jean took part in the coronation of Charles VII and in 1436 he aided in the capture of Paris. He was prominent in the conquest of Guienne and Normandy in the final years of the Hundred Years War. He participated in the Praguerie against Charles VII and was a leader of the League of the Public Weal against King Louis XI in 1465, but each time he regained favor at court.