He attended the United States Army Command and General Staff College from 1949 to 1950 and followed the operations of the UN troops in Korea during the Korean War in 1951.

After Ahnfelt passed studentexamen at Norra Latin in Stockholm in 1933, he completed university studies in history and political science before he began his military service in the Gotland Infantry Corps in Visby in 1934.

[3] He was appointed captain and company commander of the Finnish-Swedish regiment IR 13 in the Finnish Army in 1942 during the Continuation War in Finland.

[1] In 1956, the Chief of the Army, Lieutenant General Carl August Ehrensvärd appointed the then major Ahnfelt as commander of the Swedish UN battalion in the United Nations Emergency Force (UNEF).

Ahnfeldt had been Sven Olov Lindholm's closest man for six years and had at the age of 27 candidated for the National League of Sweden after Alf Meyerhöffer at the municipal elections in Östersund.

[1] Ahnfelt was promoted to colonel in 1962 and was an adviser in the Supreme Commander of the Swedish Armed Forces's working group before the Defence Act of 1963 [sv].