He was a Member of Parliament in 1945-1983 and 1987-1991, Prime Minister in 1964-1966 and Speaker of the Parliament in 1966-1968 and 1979-1983. He presented the Centre Party of Finland.
Virolainen was born near Viipuri. After the Continuation War Virolainen moved to Lohja, but he remained one of the leaders of the evacuated Karelians, and never gave up the hope that Soviet Union and later Russia would return Karelia to Finland. In the post-war elections (which completely changed the political spectrum in Finland) he became a member of Parliament. He was one of the strongest Centre-Partist leaders in the post-war era, second only to Urho Kekkonen.
Virolainen was exceptional among the Centre-partist leaders as he never became Finlandized. His Karelian roots probably prevented this. He was often reprimanded and the Finlandized political elite sometimes tried to label him as an "anti-Soviet populist", but his support among the electors was unrubbed. Virolainen was in a central position when the educational system of Finland was reformed in 1960s and 1970s. He was politically active until his death.