At the beginning of World War II, Griškevičius retreated into the Russian SFSR.

[2] He worked in press censorship (1950–1955) before moving to the Vilnius City Committee of the Communist Party of Lithuania.

[2] After the death of Antanas Sniečkus in 1974, Griškevičius succeeded him as the First Secretary of the Lithuanian Communist Party.

[1] Griškevičius was described as a Brezhnevite,[3] conservative and "mediocre apparatchik", who opposed perestroika and especially glasnost.

[4] He supported suppression of Lithuanian history and cultural heritage, replacing them with Soviet propaganda.