Kajanoja was born in Tammela, Finland, on 23 December 1942.[1][2] He joined the Communist Party being part of the fraction which was the third group after the moderates and doctrinaire faction.[3] In March 1981 he was appointed minister of labour to the cabinet led by Mauno Koivisto. He also served in the same post in the next cabinet led by Kalevi Sorsa.[4]
On 15 May 1982 Kajanoja became the chairman of the Communist Party.[5][6] He was elected to the post as a result of the conflicts between the leaders of two major fractions within the party.[3] Kajanoja was supported by the Soviet Communist Party during his tenure which ended in June 1984 when Arvo Aalto won the election.[7] In the election Aalto won 183 votes against 163 votes in favor of Kajanoja.[7]
Later Kajanoja became secretary general of the Democratic Choice.[8] On 13 August 1987 Kajanoja was nominated by the Democratic Alternative as the candidate for the presidency.[8] He could obtain only 1.4% of the votes in the elections held in February 1988.[9][10]
Kajanoja was married to Pirjo Turpeinen-Saari in the period between 1985 and 1996.[11]
