The prime minister is appointed by the president with the assent of the Lithuanian parliament, the Seimas.

This was during the original Republic of Lithuania, which lasted from the collapse of the Russian Empire until the country's annexation by the Soviet Union.

Following the ultimatum in June 1940, the forces of Soviet Union entered Lithuania, prompting President Antanas Smetona to flee the country.

Antanas Merkys, who assumed the position of acting president in accordance with the constitution, soon announced he had taken over the Presidency on a permanent basis and appointed Justas Paleckis, favored by the Soviet authorities, as the Prime Minister ahead of the "people's government".

[3] The presidency of Merkys is not recognized as legitimate in modern Lithuania[4] and Paleckis is not listed as an interwar Prime Minister in government sources.