With this association, Hilpert took part in the Battle of France and after its successful completion on 1 October 1940, he was promoted to lieutenant general.

After the daring British St Nazaire Raid revealed the poor state of western defences in March 1942, Hilpert was removed from this post and transferred to the Fuhrerreserve.

During the last stages of World War II, Hilpert commanded the German troops which had been surrounded by the Red Army in the Courland Pocket.

On 7 May 1945, Karl Dönitz, in his capacity as head of state, ordered Hilpert to surrender Army Group Courland.

Hilpert surrendered himself, his personal staff, and three divisions of the XXXVIII Corps to Soviet Marshal Leonid Govorov.