Walling was an interrogator with the U.S. Army from 1976-1980. He earned a B.A. from St. John's College in 1984 and a Ph.D. from University of Chicago in 1992. He has held several teaching and research appointments, including at Harvard University, Carleton College, U.S. Air Force Academy, Colorado College, and U.S. Naval War College, where he has been affiliated since 2000. Walling is also the author of “Republican Empire: Alexander Hamilton on War and Free Government” and co-editor of “Strategic Logic and Political Rationality.” In addition, he has written numerous articles and reviews on strategy, grand strategy, political philosophy, Thucydides and American political thought.