He was acting second secretary at the Foreign Ministry in Stockholm in 1939 and first acting secretary in 1940. He was a secretary in various negotiations with the Soviet Union in 1940 and 1941, secretary and representative of trade negotiations with Denmark in 1941 and 1942 and with Finland from 1942 to 1944. Eng was then first legation secretary in Helsinki in 1944 (temporary in 1942).[1] He served in Warsaw in 1945 where he was the Swedish government's delegate at the Provisional Government of National Unity in 1945.