Clemens August (Clementus Augustus) was born in Brussels, the son of Elector Maximilian II Emanuel of Bavaria and Theresa Kunegunda Sobieska and the grandson of King John III Sobieski of Poland.

As Archbishop of Cologne, he was one of the Electors, a Prince-Bishop of Münster, Hildesheim, and Osnabrück, and a Grand Master of the Teutonic Order.

As Elector in Bonn, his attention would be given largely to pleasure in the form of ladies, music, dancing, and erecting monuments to his glory and munificence."

In March 1761, shortly after his death, Pope Clement XIII rejected the succession of Clemens August's brother Cardinal John Theodore of Bavaria as Archbishop and Prince-Elector of Cologne since the pope entertained some doubt on John Theodore's "moral conduct".

Clemens August and his mistress Mechthild Brion had a daughter: Alessandro Cont, La Chiesa dei principi.