As an infant of six months, he succeeded his father, Rudolph, who was killed in the Battle of Crécy. His mother was Mary, daughter of Guy I of Blois. During his long minority, the regency was in the hands of his mother and Eberhard III of Württemberg.
In December 1353, John did homage for the duchy to Charles IV, Holy Roman Emperor, who made him lieutenant-general of the Empire in the Moselle country. He was facing west when, on 19 September 1356, he aided John II of France in the Battle of Poitiers, as his father had at Crécy, and where the French chivalry was mowed down by English longbowmen as before. He survived, however, unlike his father, to fight again, on the side of the Dauphin Charles in putting down the Parisian rebellion of Étienne Marcel.
He attended Charles" coronation on 19 May 1364 in Rheims, strengthening the ties to France which had steadily been building in Lorraine for the past century.
At the Battle of Auray on 29 September 1364 with John as undisputed duke and Charles dead on the field John and Bertrand du Guesclin were both taken prisoner.
He continued to aid Charles V and Charles VI to reconquer the provinces lost by the Treaty of Brétigny, but in his latter years, he distanced himself from the French court. Partly this was due to the free companies ravaging his lands and in part the royal officials who tried to litigate the relationship between John (an Imperial vassal) and his vassals.
In the end, he entered into rapprochement with Philip II, Duke of Burgundy.
John married Sophie (1343–1369), daughter of Eberhard II, Count of Württemberg, in 1361. They had:
Charles (1364–1431), successor
Frederick (1369–1415), count of Vaudémont
Isabelle (d1423), married Enguerrand VII of Coucy.
Nonetheless, he died at Paris on 22 September 1390, defending himself against a charge by the people of Neufchâteau of abuse of power.
