William McIlhenny is a visiting senior fellow at the German Marshall Fund of the United States. He was formerly at the White House as a director at the National Security Council, and at the US Department of State as a senior policy advisor. He also served as a member of the secretary of state's policy planning staff. 

During his diplomatic career spanning three decades, he held a variety of posts at US Missions in Europe and Latin America and represented the United States at UNESCO in Paris.   

He is a periodic commentator on US relations with Latin America and wider Atlantic integration. A member of the Pacific Council on International Policy, McIlhenny holds the Order of Merit of the Italian Republic and other civic and government awards and honors. He is a graduate of Georgetown University’s School of Foreign Service, held an American Political Science Association fellowship at SAIS, and has completed other studies at the University of Tel Aviv.