Jarkko received his Master's degree at the Helsinki University of Technology, where he studied Self-Organizing Maps in the research group of Academician Teuvo Kohonen. He carried out his PhD thesis work in the research group of Academy Professor Samuel Kaski. The theoretical contribution was on foundations of discriminative learning, and in the practical application he demonstrated that information retrieval benefits from probabilistic modelling of eye movements.
He carried out two post-docs at University of Helsinki, first in plant stress signalling at the research group of Professor Jaakko Kangasjärvi and then in human gut microbiome research at Academy Professor Willem de Vos' group. In 2014 he established a research group within the Center of Excellence in Molecular Biology of Primary Producers, headed by Academician Eva-Mari Aro. Jarkko's research group at NTU was established in March 2018.