Granit was elected a Foreign Member of the Royal Society (ForMemRS) in 1960 and awarded the Nobel Prize in Physiology or Medicine in 1967. Granit said that he was a "fifty-fifty" Finnish and Swedish Nobel laureate.
In the next year, 1941, Granit also received Swedish citizenship, which made it possible for him to go on with his work and live without having to worry about the war, which lasted until 1945 in Finland. Granit remained a patriotic Finn throughout his life. After the Finnish-Russian Wars, Granit kept homes both in Finland and Sweden. He and his wife are buried in Korpo, Finland.
Granit was professor of neurophysiology at the Karolinska Institutet from 1946 to his retirement in 1967.