August was born in Linz, Austria, the only surviving child to parents of Czech and Sudeten-German origin. He was baptized Catholic at the St. Matthias Church where his parents had married the previous year. His father Michael Kubíček (also born in Linz) was an upholsterer while his mother Maria Panholzer-Bláhová was born illegitimate in Rosenberg an der Moldau, legitimized by her stepfather when she was 14. His sisters Maria, Therese and Karoline died in early childhood. Kubizek later wrote that this was a striking parallel between his own life and that of Adolf Hitler, whose mother had lost four children prematurely. As the surviving sons of grief-stricken mothers, August and Adolf could not help but feel they had been spared or "chosen" by fate.