Born in the village of Naumovo, Kaluga Governorate, on 2 May 1913, Shkadov was drafted into the Red Army in October 1935 and sent to study at the Kharkov Tank School. After graduating in June 1938, he served in the 2nd Separate Tank Brigade (later the 42nd Separate Light Tank Brigade) of the 1st Separate Red Banner Army as a platoon commander of the 2nd Separate Tank Battalion, a deputy tank company commander, assistant chief of staff of the 136th Separate Tank Battalion, and chief of staff of the 216th Separate Flamethrower Tank Battalion. He fought in the Battle of Lake Khasan. In April 1941 he became senior adjutant of the 4th Flamethrower Tank Battalion of the 109th Tank Regiment of the 58th Tank Division of the 2nd Red Banner Army.