Ιοannis Kontogiannis holds a B.Sc. in Physics, an M.Sc. in Astrophysics, and a Ph.D. in Natural Sciences (Solar Physics) from the National and Kapodistrian University of Athens.

His research focuses on the physics of the solar atmosphere, with particular emphasis on the dynamics of quiet Sun, the evolution of active regions, and the prediction of solar flares and coronal mass ejections.

He was a postdoctoral researcher at the National Observatory of Athens for the KRIPIS II research programme (2014–2015) and at the Research Center for Astronomy and Applied Mathematics of the Academy of Athens for the FLARECAST project (2015–2017). From 2018 to 2024, he was a postdoctoral researcher at the Leibniz Institute for Astrophysics Potsdam (AIP), Germany. During this period, he participated in the German–Czech bilateral research project “Quiet Sun magnetic fields and Newly Emerging Flux – Dynamics, Energetics and Upper Atmospheric Response” and was a Principal Investigator (PI) of the research projects “The Evolution of Solar Active Regions toward Flares and Coronal Mass Ejections and the Role of Electric Currents” and “Detection and Dynamics of Small Solar Vortices”, funded by the German Research Foundation (DFG) and the German Academic Exchange Service (DAAD), respectively. He also participated in several international observing campaigns at the Vacuum Tower Telescope (VTT) and the GREGOR Solar Telescope in Tenerife, Spain, serving as Principal Investigator, Co-Investigator, and Support Astronomer. In 2023, he received funding from the SOLARNET H2020 project for observing time at the Swedish 1-m Solar Telescope (SST) on La Palma, Spain. He taught the graduate courses Solar Physics, Solar–Terrestrial Relations, and Digital Image Processing at the University of Potsdam and supervised an undergraduate thesis.

From 2024 to 2026, he worked at ETH Zurich and the Istituto Ricerche Solari Aldo e Cele Daccò (IRSOL) in Locarno, Switzerland, where his research focused on the analysis of observations from the Solar Orbiter mission. During this period, he also supervised an undergraduate thesis.

He is a member of the International Astronomical Union (IAU), the European Physical Society (EPS), and the Hellenic Astronomical Society. He is an elected member of the Board of the European Solar Physics Division (2021–2024 and 2024–2027), where he holds the position of Press Officer. He also chairs the Operational Activities, Infrastructure, Data, and Models (OAIDM) Working Group of the European Space Weather and Space Climate Association (E-SWAN).

Alongside his research activities, he has maintained a long-standing commitment to science communication. From 2007 to 2015, he worked as a science educator at the Interactive Science and Technology Exhibition of the Eugenides Foundation, where he designed and delivered public lectures, live science demonstrations, workshops, and educational activities for schools, general public, science festivals, and television shows. From 2016 to 2018, he developed and delivered educational programmes at the Aikaterini Laskaridis Foundation. Between 2016 and 2024, he was a member of the editorial team of Prisma inlet of the newspaper Avgi, where he authored dozens of popular science articles.