 In 1962, he finished his studies with a PhD in Indo-European linguistics and passed the final teachers' exam for Latin and [Greek].From 1957 until 1962, Mittelberger was an assistant at the Institute of Indology in Vienna.In 1963, he became a scientific clerk for Indo-European linguistics and the Hittite language at the "Institut voor Osterse Talen" at the University of Utrecht.