Thomas M. T. Niles retired from the United States Foreign Service in September 1998 following a career of more than 36 years. In the Foreign Service, he served as Ambassador to Canada (1985-89), Ambassador to the European Union (1989-91), Assistant Secretary of State for Europe and Canada (1991-93), and Ambassador to Greece (1993-97).
Earlier in his career, he served in Belgrade, Moscow (twice), and the United States Mission to NATO in Brussels as well as in the Department of State. On February 1, 1999, he became President of the United States Council for International Business (USCIB), which advances the global interests of American business both at home and abroad, promoting an open system of world trade, finance, and investment. It is the U.S. affiliate of the International Chamber of Commerce (ICC), the Business and Industry Advisory Committee (BIAC) to the OECD, and the International Organization of Employers (IOE).
On April 15, 2005 Ambassador Niles retired as President of USCIB and became Vice Chairman of the Council.