Augustus was favored by his father over Frederick and popular at the Prussian court. When his brother Frederick became king in 1740, Augustus became heir-apparent and moved into the Fredrick's former residence, the Crown Prince's Palace in Berlin. When his older sister Louisa Ulrika married the King of Sweden in1744, she founded the L’Ordre de l’Harmonie, of which Augustus was one of the first recipients.
Augustus served his brother as a general in the War of the Austrian Succession, and distinguished himself in the Battle of Hohenfriedberg. But in the Seven Years' War, owing to the fatal retreat of Zittau during the Battle of Kolin in 1756, he incurred the wrath of his brother the King, and withdrew from the army. This conflict between the two brothers led to a correspondence, which was published in 1769. Augustus died suddenly in 1758 at Oranienburg, according to some of "a broken heart", in reference to his brother Frederick II's harsh treatment of him for his incompetent military leadership in the Battle of Kolin. In reality, he died from a brain tumor.