Atte Harjanne has been an MP for the Finnish Greens (Vihreä liitto) since 2019. He chaired the Green parliamentary group in the Finnish parliament between 2021 and 2024. He is also a member of Helsinki City Council. Before entering parliament, Atte worked as a researcher at the Finnish Meteorological Institute, studying economic and social impacts of climate change. He is a reserve captain in the Finnish Defence Forces.