In November 1779 Forster was appointed Professor of Natural history and Mineralogy at the University of Halle, and director of the Botanische Garten der Martin-Luther-Universität Halle-Wittenberg, where he remained until his death.
Pada November 1779 Forster diangkat menjadi Profesor sejarah alam dan mineralogi di Universitas Halle , dan direktur Botanische Garten der Martin-Luther-Universität Halle-Wittenberg, hingga kematiannya.