Early in his career he was identified as a Baptist, but later was credentialed by the Independent Fundamental Churches of America (IFCA).
At Dallas he was a protege of Lewis Sperry Chafer, bible teacher and founding president of the Seminary.
After serving as a pastor at several churches (e.g. Buffalo, New York), Unger taught for a year at Gordon College.
In retirement Dr. Unger led Bible conferences and wrote on Old Testament, theological and practical topics.
After retiring from Dallas Seminary due to health concerns and the loss of his first wife, Unger returned to his native Maryland where he and his second wife, Pearl, bought "Birdhaven," an arboretum estate on the Magothy River near Severna Park in Anne Arundel County.