 Radnički won the Subassociation league in 1934, 1935, 1938 and 1939, however it only managed to qualify once to the national league, in the 1935–36 season.They had a fierce rivalry with FK Šumadija 1903 in this period.During the World War II, the Kingdom of Yugoslavia was invaded and partitioned by the Axis powers, and Kragujevac were occupied by Nazi Germany soldiers and underwent a number of tragic days during war.