[1] His uncle Georg Albrecht acted as regent until 1664, when Christian Ernst was declared an adult and assumed the government of his principality.

From 1668 the arming of his own dominion (which was intended originally to aid the emperor) strained state finances and exposed Bayreuth to military dangers.

The military ambitions of Christian Ernst made him an important political ally in spite of the small territories that he ruled.

[citation needed] In Dresden on 29 October 1662, Christian Ernst was married to Erdmuthe Sophie, only surviving daughter of his paternal aunt, Magdalene Sibylle, and her husband John George II, Elector of Saxony.

They had six children, three of whom died in infancy: In Potsdam on 30 March 1703 (five months after the death of his second wife), Christian Ernst married thirdly Elisabeth Sophie of Brandenburg.