Mr. Winternitz is Performing the Duties of Deputy Assistant Secretary of Defense for East Asia in the Office of the Secretary of Defense (OSD).  Mr. Winternitz is also the Principal Director for East Asia Policy. He previously served as the Acting Deputy Assistant Secretary of Defense for East Asia from October 2023 to May 2024 and as Acting Deputy Assistant Secretary of Defense for Europe and NATO Policy from November 2018 until October 2019 and from July 2020 until February 2021.  As the Principal Director for East Asia, Mr. Winternitz supports the Secretary of Defense in the formulation and implementation of defense policy the formulation and implementation of defense policy and bilateral defense relations with major U.S. Allies Australia, Japan, and South Korea as well as policy towards New Zealand, North Korea, fourteen Pacific Island Countries, and Antarctica. 

From 2010 until 2018, Mr. Winternitz held several roles in the East Asia office, including as the Acting Principal Director for East Asia from January 2017 until October 2018, Director for Japan from February 2015 until January 2017, and Senior Country Director for Japan from October 2012 until February 2015.  From 2010-2012, Mr. Winternitz completed a Mansfield Fellowship, during which he spent one year in Japan working within the Japanese Ministry of Defense and Ministry of Foreign Affairs. 

From April 2004 until April 2010, Mr. Winternitz held several roles in the Europe and NATO Policy office, including Deputy Director for European Policy from 2008-2010 and at various times the country director for 19 country portfolios.

Mr. Winternitz earned a Juris Doctor and Master’s Degree in International Affairs from American University in Washington, D.C. and a Bachelor’s Degree in International Studies and Political Science from the University of North Carolina at Greensboro.