Wrang was born on 27 January 1917 in Lidingö, Sweden, the son of lieutenant colonel Ragnar Vrang and his wife Hild (née Stenhammar).

Wrang passed studentexamen in Gävle in 1936 and was commissioned as an officer in 1939 and was assigned as a second lieutenant to Hälsinge Regiment (I 14).

[2] Instead, Wrang joined the Finnish Army during the Winter War and was promoted to fänrik and took part in the battle of Märkäjärvi.

[1] Returning to Sweden in April 1940, he re-entered the Swedish Army for fear that his country would share the fate of Norway and Denmark.

[2] On discovering a Finnish volunteer battalion was being raised, he applied for an immediate transfer to the unit's base at Stralsund training camp, which was granted.

[2] Promoted to Obersturmführer on arrival, his application for transfer to Finland was granted following the discovery that the volunteers would be deployed in Ukraine.

[2] He then served with the Finnish Volunteer Battalion of the Waffen-SS of the 5th SS Panzer Division Wiking for several weeks in 1941.

In 1953, he was appointed captain in the Svea Life Guards (I 1) and from 1954 to 1956 he attended the Royal Swedish Army Staff College.