William Green Miller served as the United States Ambassador to Ukraine under Bill Clinton, from 1993 to 1998.

In 1959, he joined the United States Foreign Service. From 1959 to 1964, he served as a diplomat in Iran. He then worked as a staffer for Secretary of State Dean Rusk, and in the Senate for John Sherman Cooper.

From 1981 to 1983, he served as Associate Dean and Professor of International Politics at the Fletcher School of Law and Diplomacy at Tufts University. In 1986, he was a Research Fellow at the Harvard Institute of Politics and became President of the American Committee on United States-Soviet Relations. From 1993 to 1998, he served as the United States Ambassador to Ukraine.

He is a Senior Policy Scholar at the Woodrow Wilson International Center for Scholars in Washington, D.C.. He is also a member of the Council on Foreign Relations, the International Institute of Strategic Studies, and the Middle East Institute. He is the co-Chairman of the Kyiv Mohyla Foundation of America and a Director of The Andrei Sakharov Foundation. He consulted for the John D. and Catherine T. MacArthur Foundation.