Eliyahu Ashtor (formerly Eduard Strauss) was born in Vienna. He attended the Theological Seminar in Vienna for five years. In 1936 he graduated as Doctor of Philosophy in Oriental studies and history at the University of Vienna.
In 1938, following the annexation of Austria to Nazi Germany, he immigrated to Eretz Israel, then British Mandate of Palestine and changed his name from Eduard Strauss. From 1939 to 1957 he was librarian at the oriental department of the National and University Library at the Hebrew University of Jerusalem. Ashtor continued his studies at Hebrew University and received his Ph.D. in Philosophy.
He taught at Hebrew University from 1948 until 1954 under a research fellowship and a teaching contract. In 1955 he was admitted to the faculty as a lecturer of Arabic studies. Ashtor was admitted to the Faculty of Law in 1956 as a lecturer in Islamic law. He was in the faculty until 1968. In 1963 Ashtor was appointed to associate professor and then professor, in 1969. From 1967 to 1968 he was Directeur d’etudes associes, at the ‘Ecole Pratique des Hautes Etudes’, Section des sciences economiques, Sorbonne, Paris. He was visiting professor at the department of history at Harvard University from 1968 to 1969 and from 1972 to 1973 he was visiting lecturer at the University of Zurich, Switzerland.