Hannes was a Research and Project Assistant to Federica D’Alessandra, at the time Executive Director of the Programme on International Peace and Security at the Oxford Institute for Ethics, Law and Armed Conflict (ELAC). He obtained a DPhil in public international law in 2022 under the supervision of Professor Dapo Akande. His research focused on penal proceedings conducted by non-state armed groups and was supported by the Arts and Humanities Research Council (AHRC). Hannes holds law degrees from the University of Graz and University College London (UCL) where he was awarded the Georg Schwarzenberger Prize in International Law by the Institute of Advanced Legal Studies (University of London).
Before coming to Oxford, Hannes worked as a legal advisor on human rights, constitutional law and judicial affairs in the Austrian Parliament. He also clerked at the Israeli Supreme Court in Jerusalem and was an intern at the United Nations Offices in Vienna and Geneva.