Daniel R. Green is a Research Fellow in the Allison Center for National Security at The Heritage Foundation. In addition to writing about national security topics, he is also the Editor of the Index of U.S. Military Strength. 

He previously served as the Deputy Assistant Secretary of Defense for Strategy and Force Development (2019–2021), where he was responsible for defense strategy, force development, and strategic analysis within the Office of the Secretary of Defense (Policy) and advised the Assistant Secretary of Defense for Strategy, Plans, and Capabilities. His office develops the National Defense Strategy, the Defense Planning Guidance, as well as various Defense Planning Scenarios. Prior to his appointment, he served as a Defense Fellow at The Washington Institute for Near East Policy (2011–2014; 2016–2019). He previously served in the Office of the Secretary of Defense (Policy) in 2001–2003 and from 2008–2009. 

He has authored, co-authored, or co-edited five books, including The Valley’s Edge: A Year with the Pashtuns in the Heartland of the Taliban (Potomac Books, 2011), Fallujah Redux: The Anbar Awakening and the Struggle with al-Qaeda (Naval Institute Press, 2014), co-authored with MajGen William F. Mullen III, USMC, In the Warlords’ Shadow: Special Operations Forces, the Afghans, and Their Fight Against the Taliban (Naval Institute Press, 2017), Front Toward Enemy: War, Veterans, and the Homefront (Rowman & Littlefield, 2021), and co-edited Confronting China: U.S. Defense Policy in an Era of Great Power Competition (Bloomsbury Academic, 2024). 

He has also published a book chapter titled “Organizing Like the Enemy: Special Operations Forces, Afghan Culture, and Village Stability Operations” in Our Latest Longest War: Losing Hearts and Minds in Afghanistan (University of Chicago Press, 2017), edited by Dr. Aaron O’Connell. Dr. Green has written over sixty-six journal articles, op-eds, and policy analysis studies for Proceedings, Marine Corps Gazette, Armed Forces Journal, Strategic Studies Quarterly, Military Review, Special Warfare Magazine, Small Wars and Insurgencies, Foreign Policy, The New Republic, and Interagency Journal, among other publications. 

Dr. Green is an active drilling reserve officer with the U.S. Navy and a veteran of OPERATION ENDURING FREEDOM, OPERATION IRAQI FREEDOM, and OPERATION INHERENT RESOLVE. He also served with the U.S. Department of State as the political advisor to a Provincial Reconstruction Team in southern Afghanistan. He is a recipient of the Secretary of Defense Medal for Outstanding Public Service (2021), the Office of the Secretary of Defense’s Exceptional Public Service Award (2009), the U.S. Department of State’s Superior Honor Award (2005), and the U.S. Army’s Superior Civilian Honor Award (2005). He has also been personally commended by then-Chairman of the Joint Chiefs of Staff General Peter Pace (2006). 

Dr. Green earned a bachelor’s degree in political science, cum laude, from American University; a bachelor’s degree in history & CLEG (Communications, Legal Institutions, Economics, and Government), cum laude, from American University in 1998; a master’s degree in international affairs from Florida State University in 1999; and a PhD and an MPhil in political science from George Washington University in 2012.