In August 1941, Gascoigne was promoted to the diplomatic rank of embassy Counsellor.

Later, he was embassy counsellor in St. Petersburg and participated in the European travels of Naser al-Din Shah Qajar and then Mozaffar ad-Din Shah Qajar.

He started working for the Norwegian Ministry of Foreign Affairs in 1955, and served as embassy counsellor in the United States from 1965 to 1969, before becoming sub-director in the Ministry of Foreign Affairs.