Öpik was Professor of Geology and Palaeontology, Estonian State University at Tartu 1930-1944. He and his family emigrated to Australia in 1948 and was employed as geologist at the Bureau of Mineral Resources, Canberra until his retirement in 1964. His major work in Australia was on the Cambrian and Early Ordovician stratigraphy and palaeontology of northern Australia.