This paper surveys the history of the United States policy towards European integration from 1945 up to 1968 before President Nixon came into office. Drawing on a detailed analysis of the documents mostly obtainable from the official websites of the US Department of State, the US National Archives, and the EU Historical Archives, the paper argues that it was the European geopolitical and economic context after the Second World War and the United States national interests which moulded this country’s pro-European integration policy. Thus, the paper will begin with an analysis of the search for global influence between the United States and the Soviet Union before examining how the United States redefined its core interests in recognition of the Soviet threat. Then, it will explore the role that the United States played in reconstructing Western European economy and defending it physically. Also, it is argued that the United States and Western Europe took concerted action together to create the European Coal and Steel Community (ECSC), European Economic Community (EEC), and the European Atomic Energy Community (EAEC or Euratom), the very first supranational institutions which have made the European integration process irreversible. It will be concluded that the vitality of the European integration project depended on US economic and political capital for its success.