Although his line was a cadet branch, his son Joachim Frederick would later inherit the Duchy of Schleswig-Holstein-Sonderburg-Plön.
who was one year older, made a Grand Tour of European countries, visiting, inter alia, England and France.
Augustus became an officer in the army of Brandenburg-Prussia and was promoted to General of the Infantry on 20 August 1664.
On 21 December 1674, he was appointed governor of Minden, as a reward for his bravery in the war against the Ottoman Empire.
When Elector Frederick William died in 1688, he retired from the Brandenburg army and settled at Nordborg Castle.