After graduation, he began teaching at Swarthmore College where he remained until 1956. He relocated to the University of Wisconsin–Madison where he taught from 1956 through 1975. There, Curtin and fellow historian Jan Vansina established a department of African languages and literature during 1956, as part of one of the first academic African studies programs established at a college in the United States. From 1975 until the time of his death he was a member of the faculty of Johns Hopkins University .