During Ljung's eight years as Supreme Commander many events of importance for Swedish security and defense policy occurred.

[3] Ljung was commissioned as an officer 1944[3] and was assigned as a second lieutenant to the Swedish Army Signal Troops the same year.

Ljung was promoted to captain in the Swedish Army Signal Troops in 1953 and attended the United States Army Command and General Staff College at Fort Leavenworth, Kansas from 1956 to 1957 when he became captain of the General Staff.

[2] Ljung's time as Supreme Commander was marked by major transformations in the Swedish Armed Forces and by the constant financial pressure.

[5] It also consisted of renewal of the war planning, major military equipment projects, such as the Saab JAS 39 Gripen, a new kind of armed forces training and reorganization of both the leadership and the command organization.

His report on the whole situation excluded the possibility that the submarine accidentally ended up in Swedish territory, and he pursue in the coming years the issue of higher allocations to the military to fight the submarine intrusions which was considered coming from the Soviet Union.