Ramanauskas was born to Lithuanian immigrant family in the United States. In 1921, his family returned to Lithuania, bought of land in Bielėnai near Rudamina, and took up farming. Ramanauskas graduated from Galiniai primary school in 1930, and from Lazdijai secondary school in 1937. He continued his studies at the Klaipėda Pedagogical Institute (now Vilnius Pedagogical University). Just before graduation the Klaipėda Region (Memel Territory) was ceded to Nazi Germany; therefore the institute was evacuated to Panevėžys. The same year, Ramanauskas enrolled into the Kaunas War School. He graduated with the rank of second lieutenant in the reserve forces. His class of 1940 was the last class to graduate from the war school before Lithuania was occupied by the Soviet Union in June 1940.