He is a researcher at the Institute for History of Religions (Institutul de Istorie a Religiilor), Romanian Academy. He is also a Romanian historian, ethnologist, cultural anthropologist, literary critic and novelist. Noted for his work on the history of religions, theology, Jewish studies, and the history of antisemitism, he is a researcher at the National Museum of Romanian Literature in Bucharest, a member of the Romanian Academy's Folklore and Ethnology Commission, and a member of the International Union of Ethnological and Anthropological Sciences in London. Specialized in the history of mentalities and the investigation of rituals and magic, he is, together with Ioan Petru Culianu, one of Mircea Eliade's leading disciples in Romania.

He is the brother of American poet Valery Oisteanu.