When his father died in 1535, John had to share the County of Rietberg with his older half-brother Otto IV.

John then moved his mercenaries from Esens to Rietberg and attacked Count Bernhard VIII of Lippe.

Lippe, Paderborn and East Frisia also sued each other in the court of the Lower Rhenish-Westphalian Circle.

Imperial troops joined the siege of Rietberg and in June 1557, the city was starved and had to capitulate.

Initially, he was held at the Imperial castle at Büderich (near Wesel); in 1560, he was transferred to Cologne, where he died in captivity in 1562 and was buried.