After the occupation of Lithuania by the Soviet Union in June 1940, Lithuanian diplomats did not recognize the new Soviet government and established the Lithuanian Diplomatic Service that functioned in conditions of exile, continued to represent independent Lithuania, and preserved the legal continuity of the state.

After graduation from the Panevėžys Gymnasium, he received a stipend form the Ministry of Foreign Affairs and attended the University of Paris where he studied law and political science.

In this capacity, Bačkis participated in the assemblies of the Baltic Entente and League of Nations as well as the coronation of King George VI and Queen Elizabeth.

Ambassador Petras Klimas retreated south with Vichy France officials leaving Bačkis as the senior diplomat in Paris.

[4] Bačkis' family in Lithuania was persecuted by the Soviets; his brother Juozas was deported to Siberia in June 1941 where he died a year later.

[2] After the war, France did not officially recognize Lithuanian, Latvian, or Estonian Diplomatic Services, but allowed them to function unofficially.

In 1948, Bačkis made contacts with Juozas Lukša, an anti-Soviet partisan who managed to escape the Iron Curtain, and helped him spread information about the armed struggle.

[3] Bačkis also urged reestablishment of the Lithuanian Catholic Academy of Science and actively presented research papers in its sessions.

[4] After the death of Povilas Žadeikis, Lithuanian ambassador in Washington, D.C., in 1957, there was a need to strengthen the American mission.

[6] By 1980, the gold reserve was exhausted and the Lithuanian diplomatic service faced the possibility that it would have to close due to lack of funds.

In January 1980, the Department of State organized a meeting between Bačkis and Anatols Dinbergs, head of the Latvian Diplomatic Service.

In the meeting, Dinbergs agreed to loan $120,000 (equivalent to $444,000 in 2023) annually to the Lithuanians from the Latvian gold reserves.

A group of Lithuanian Americans petitioned Stephen Aiello, Special Assistant to President Jimmy Carter for Ethnic Affairs, and the position was reversed in fall 1980.

Built in 1909, the building sorely needed major repairs, particularly after the May 1979 bombing at the next-door Cuban Interests Section.

[10] After a few months in a hospital, he returned to work but poor health forced him to resign in favor of Stasys Lozoraitis Jr. in November 1987.

After the death of Jurgis Baltrušaitis in 1988, Bačkis decided to return to Paris and, health permitting, resume his unofficial position there.