Joseph DeThomas
Ambassador, retired

Joseph DeThomas
Joseph DeThomas has worked in the field of international affairs as a practitioner, academic or outside expert for 45 years.

Joseph DeThomas has worked in the field of international affairs as a practitioner, academic or outside expert for 45 years. After entering the U.S. Foreign Service in 1977, he served abroad in Iran, Germany, Mexico, Ethiopia, Austria and finally as U.S. Ambassador to Estonia. He served numerous tours in Washington in the Department of State frequently as an expert in preventing the spread of weapons of mass destruction. This career path culminated with his service as Principal Deputy Assistant Secretary of State for Nonproliferation. These duties frequently included leadership roles in dealing with the threat of Iranian and North Korean WMD as well as with the dangers posed by nuclear weapons in South Asia. These duties also involved creating innovative U.S. government assistance programs and other operations to address the threat posed by proliferation in Russia and other successor states to the USSR. His other area of expertise is European Affairs. He served as Director for European Union issues under Secretary Albright. As Ambassador to Estonia, he oversaw the U.S. role in preparing Estonia for NATO membership. He has also worked extensively with both the European Union and NATO.

Outside of his diplomatic work, Ambassador DeThomas served as the Director for Non-proliferation Programs at CRDF Global, an NGO that uses innovative programs of scientific engagement to prevent proliferation. He designed programs to deal with the legacy of WMD development in Iraq and Libya. Ambassador DeThomas taught international affairs at the graduate level at the National War College and at Penn State’s School of International Affairs.

He has received a number of awards from the Department of State including a group award for valor in Iran, for earthquake rescue in Mexico, and for humanitarian work during the Ethiopian civil war. He received Estonia’s highest award for his work in Estonia’s NATO accession and was given the Alumni Achievement Award by Penn State’s College of Liberal Arts in 2015.

Ambassador DeThomas was born in Easton, Pennsylvania. He lives with his spouse Valerie DeThomas and their children in Alexandria, VA. Until her untimely passing, Ambassador DeThomas was married to Wellesley alumna and national intelligence and foreign policy expert, Leslie Davidson.