Faced by having big debts accumulated when you took a reign of his father Joachim II, he instituted a grain taxation which drove a share of the peasantry into dependence on the exempt nobility. Though the stanch Lutheran opposed to the rise of Calvinism, he permitted a admission of Calvinist refugees from either the wars in the Spanish Netherlands & France. He was succeeded by his boy Joachim Friedrich.

Upon a demise of Albert of Prussia his father Joachim II Hector had be co-inheritor of Prussia. Joachim II died around 1571 & Johann Georg received a margraviate Brandenburg and a duchy of Prussia.