In 1774, Karl August got married to the Saxon princess Maria Amalie. Their only son, Karl August Friedrich, however, already died at the age of eight in 1784. Thus, the hereditary rights fell upon Karl August's younger brother Max Joseph.
The Wittelsbach in Munich and Mannheim did not have descendants entitled to an inheritance. Elector Maximilian Joseph III. resided in Munich until 1777. His death also marked the end of the Bavarian line of the dynasty. He was thus suceeded by Karl Theodor of Palatine, who moved his residence from Mannheim to Munich. His only marital son had already died in 1761 during birth. Therefore, Karl August had the chance to succeed in Mannheim as well as in Munich.