Entering upon a military career, he became colonel of an infantry regiment in the Army of Flanders, and acted as military governor of Maastricht during the 1632 siege. On 3 August 1633 his barony, Lede, was raised to a marquisate in recognition of his service to the Spanish Monarchy. Between 1635 and 1640, he was governor of the Duchy of Limburg and the Overmaas. In 1636 he conquered the County of Valkenburg. From 1640 until 1646 he was Stadtholder of Upper Guelders.