Guiseppe was the second son of
Vincenzo Gonzaga, Duke of Guastalla and his second wife, Princess Maria Vittoria Gonzaga of Guastalla (1659-1707). Giuseppe was mentally unstable, and his condition deteriorated over time. When his elder brother Duke
Antonio Ferrante died in an accident in 1729, Giuseppe was the only remaining male member of the Gonzaga family, so he became duke. == Marriage ==