He received his Bachelor of Arts in history from the University of Maryland and his Doctor of Philosophy from Georgetown University in 1967.
He is an expert on the ancient history of the South Caucasus. He spent seven years in Europe with the United States Air Force and studying. The same year he joined the history department of Rowan University, where he taught Byzantine and Russian history for more than 30 years.
After retiring from Rowan University in July 1999, Professor Hewsen lectured at University of Chicago, Columbia University, California State University, Fresno and University of California, Los Los Angeles