Relander was born in Kurkijoki, Finland. He studied agricultural chemistry but when his efforts to find a senior lecturer position failed, he became politically active in the Finnish Agrarian Party. He was elected into parliament 1910. By 1917 he had become one of the leaders of the party.
After independence, his political career went well but in 1920s he did not have enough support in his own party to become a minister. He became his party’s presidential candidate just days before the election and was elected mainly because he was seen as alternative to Risto Ryti.
As a president, Relander was politically inexperienced and young. Politicians did not take him seriously and he had no particular policy or program, which decreased his support. He was continually compared to Kaarlo Juho Ståhlberg. His continual state visits and trips also drew criticism. Even the governments during his term tended to be minority-based, thought this was not the president’s fault.
In 1931 Relander realized he would not be re-elected and sabotaged the prospects of Kyösti Kallio, so that Pehr Evind Svinhufvud, Relander’s former prime minister, was elected.
Relander died in 1942 of heart failure.