In 1472, his uncle Charles of Artois, Count of Eu, died, and having no legitimate children, his title also passed to John.

John fought in the army of his stepfather Philip the Good and was active in Picardy (1434), Calais (1436), Luxembourg (1443), and Flanders (1453).

But he clashed with Philip's successor, Charles the Bold, and he defected to King Louis XI of France.

He fought alongside Louis XI in the War of the Public Weal and became Lieutenant General of Normandy.

They had one child: John's final marriage was on 11 March 1480, in the château de Châlus-Chabrol (Limousin), to Marie d'Albret (c. 1454-1521).