Its commanders during that time were : During Operation München, when Romania entered World War II on the side of the Axis in June–July 1941, the First Army was in the interior of Romania while the Third and Fourth Armies formed the main Romanian assault force.

On August 23, Marshal Ion Antonescu was dismissed by King Michael I, and Romania declared war on Germany and Hungary some days later.

The Soviets took control of the oilfields in the Ploiești area, and the Romanian Army was used to fight German forces on the Eastern Front.

In its campaign from August 1944 to May 1945, the Romanian Army lost some 64,000 men killed.

German resistance in the east was now limited to small pockets scattered across Germany, Czechoslovakia, and Austria.