Ambassador Donald A. Mahley is currently serving as the Acting Deputy Assistant Secretary for Threat Reduction, Export Controls, and Nego­ti­a­tions.  As such, he has the responsibility for chemical and bio­lo­gi­cal wea­pons threat reduction, missile threat reduction, conventional weapons threat reduction, and export controls.

Previously, Ambassador Mahley was the Deputy Assistant Secretary for Arms Control Implementation in the Arms Control Bureau of the Department of State.  He served as the Special Negotiator for Chemical and Biological Arms Control issues from April 1999 to September 2002.  Ambassador Mahley heads the United States Delegation to Biological Weapons Convention activities and is the Managing Director of the United States National Authority for implementation of the Chemical Weapons Convention.  From 1993 until 1999, Ambassador Mahley served as Deputy Assistant Director and Acting Assistant Director of the Multilateral Affairs Bureau of the Arms Control and Disarmament Agency.  While still in military service, from 1990-1992, he served as Associate Assistant Director of the Multilateral Affairs Bureau and led U.S. efforts to conclude the Chemical Weapons Convention.  Prior to his term in ACDA, Ambassador Mahley served six years (1984-1990) as Director of Defense Policy and Arms Control on the National Security Council staff.  He arrived at the NSC after four years in the U.S. Mission to NATO, having served as Deputy Director of the Defense Plans Division for the U.S. Ambassador to NATO.

Ambassador Mahley is a retired United States Army officer, Ordnance, in the rank of Colonel.  He served overseas in Viet Nam, Turkey, and Belgium during his active duty with the United States Army, and successfully held three command positions during his military career.  He also served as an Assistant Professor of Social Sciences at the United States Military Academy and an Associate Professor of Military Strategy at the National War College.

Ambassador Mahley is a graduate of Purdue University (1964) and of the Graduate School of Public and International Affairs at the University of Pittsburgh (1971).  His military education includes Air Defense, Nuclear Weapons, Command and General Staff College and National War College credentials.  Ambassador Mahley was born in Peru, Indiana on 16 June 1942.  He is married to Julianna (nee Stephenson) Mahley.  They reside in Vienna, Virginia.