During the First World War, the 1st Division was activated to ensure Norwegian neutrality.

Training was intensified with several large-scale exercises and units performed guard duty at important sites such as arsenals and industrial facilities.

[1] Following the German invasion of Norway in 1940 the Norwegian 1st Division, commanded by Major General Carl Johan Erichsen, was responsible for defending the land areas on both side of the Oslofjord against the invading troops.

[2][3][4] The 1st Division was re-established in May 1952 with headquarters in Ski, tasked with the defence of South Norway.

The 1st Division was disbanded by 1 January 1963, its personnel dispersed and its tasks reassigned to the District Command Østlandet.