He studied Lithuanian, Russian and French at the Vytautas Magnus University, in Kaunas. In 1936, Venclova visited the USSR, and became fascinated with the Soviet system and its culture. Before the outbreak of the Second World War, he worked as a teacher, and was the editor of the procommunist journals, Trečias frontas (Third Front), and Prošvaistė.
In 1940, he was briefly appointed as Minister of Education of the Lithuanian SSR following the Soviet invasion in 1940. In 1940, he was elected as a representative to the "People's Seimas" and went to Moscow as part of the delegation requesting that Lithuania be incorporated into the USSR. After the German invasion in 1941, he retreated with the Red Army and lived in Russia during the Nazi occupation, returning in 1944.
In the following years, he faithfully served the Soviet government.
In 1947, he received the Stalin Prize. Venclova wrote the original words for the anthem of Lithuanian SSR, and the Lithuanian version of the Soviet anthem. After Joseph Stalin's death, the second stanza of the lyrics were changed by Vacys Reimeris to remove any mention of Stalin. Between 1954 and 1959, he was Chairman of the Lithuanian Writer's Union.
His son, the poet Tomas Venclova, was a prominent dissident.