A member of the Centre Party, he served in the Parliament from 1966 to 1987 and as Minister of Agriculture and Forestry from 1 August 1973 to 13 June 1975 and again from 30 November 1975 to 29 September 1976.

[1] Linna graduated as an agrologist from Small farming advisory college in Hyvinkää in 1952, worked as an agricultural consultant in the Northeast region in 1953–1954, worked as executive director of the Association of Agricultural Producers in Central Ostrobothnia in 1954–1966, and as a farmer in his home municipality of Perho since 1962.Linna served on the Perho municipal council in 1965–1992.

Linna was one of the strictest opponent of the Finnish EU-Membership in his party and was against, among other things, accepting asylum seekers and refugees.

Linna was considered to have also belonged to the so-called black dozen that operated within the Center Party.

For the 2019 parliamentary elections, Heimo Linna wrote an article in Perhonjokilaakso newspaper, where he announced that he supports Paavo Väyrynen's Seven Star Movement, so that Finland could avoid membership in the North Atlantic Treaty Organization.