Professor Kangasjärvi graduated as BSc. in plant physiology and genetics in the University of Oulu in 1984 and two years later as MSc. He did his PhD in plant physiology and genetics in the University of Minnesota in 1991.
Jaakko Kangasjärvi was the group leader of the Forest biotechnology research program in the Institute of Biotechnology in 1997–2002. He acted as Professor of plant physiology and molecular biology in the University of Turku in 2001–2003. Since 2003 he has been holding the position of Professor of Plant Biology in the University of Helsinki.
Jaakko Kangasjärvi is also a member and a vice-director of the Academy of Finland Center of Excellence in Molecular Biology of Primary Producers (2014–2018).