Busch was born on 6 July 1885 at Essen in the Ruhr district of Germany. In 1904, having graduated from the Gross Lichterfelde Cadet Academy, he joined the Imperial Army as a Fahnenjunker (officer cadet). He was initially posted to the Westphalian 13th Infantry Regiment but was later assigned to the 57th Infantry Regiment, in which he was commissioned a Leutnant (second lieutenant). In 1913, he was promoted to Oberleutnant (first lieutenant) and received further training at the War Academy.
