Harry W. Pfanz graduated from Ohio State University in 1943, followed by service in the U.S. army in World War II. He then became a historian, first for the Department of the Army then for Gettysburg National Military Park for ten years. He received a doctorate in history from Ohio State University in 1958. He has also served as the Chief Historian of the National Park Service from 1974 until his retirement in 1981.