Ambassador Brill had a 35-year career in the U.S. Foreign Service. He was Ambassador to the IAEA 2001-2004 and Ambassador to Cyprus 1996-1999. In between those assignments, he was the Principal Deputy Assistant Secretary and acting-Assistant Secretary for the State Department’s Bureau of Oceans and International Environmental and Scientific Affairs, during which time he participated in or led U.S. delegations to international meetings on climate change and a number of other environmental issues. In his final Foreign Service assignment, he was the founding Director of the U.S. National Counterproliferation Center (NCPC), which is part of the Office of the Director of National Intelligence.

Ambassador Brill has written and spoken on the subjects of countering the proliferation of weapons of mass destruction, nuclear security, WMD terrorism, the impact of globalization on U.S. national security interests, and the environment as a national security issue. He has written op-eds for the New York Times, the International Herald Tribune, the Washington Post and other publications.