He began his teaching activity at the Geology Department of Bucharest University, where he was a teaching assistant, lecturer and associate professor between 1949 and 1961. He was eliminated from the teaching system for political reasons, and he started again his university career after 1989, when, together with prof. Dolfi Drimer, he founded the Ecological University, where he was appointed as Dean of the Faculty of Natural Sciences (afterwards transformed in the Faculty of Ecology). Between 1949 and 1994, Bleahu worked as a geologist, a researcher and as a manager (including General Manager) at the Geological Institute of Romania.
