At the age of 13, he was legally adopted by his stepfather, who was Polish, and took on the surname Wilimowski. At home, he spoke German for the most part, while in public he often spoke a Silesian dialect of the Polish language. Officially a citizen of Poland, he referred to himself as an Upper Silesian ("Górnoślązak" - Oberschlesier).
His parents, Ernst-Roman and Paulina, were German. His father, a soldier for the German Empire, died on the Western Front in the First World War. His mother sent him to a German kindergarten, a German primary school and, when he was nine years old, to the German football team 1.