Born in Thuringia, Boineburg-Lengsfeld joined the army of Imperial Germany as an Fahnen-junker (officer cadet) in 1910. He was commissioned in the light infantry and fought in World War I. In the interwar period, he served in the Reichsheer and then the Wehrmacht. He led the 1st Rifle Regiment from 1938 to 1939 before being given command of the 4th Schützen (Rifle) Brigade[1] of the 4th Panzer Division which fought in the Invasion of Poland.