Ferrante played a part in the War of the Mantuan Succession when, as a distant Gonzaga cousin, he claimed the Duchy of Mantua after the extinction of the senior male branch of the House of Gonzaga in December 1627. He was nominally supported by Habsburg Emperor Ferdinand II, who really sought to re-attach the Duchy of Mantua to the Holy Roman Empire. His attempt failed as the French candidate Charles of Nevers became the new Duke.