In 1938, curators from the Museum of Modern Art installed their first international exhibition, Three Centuries of American Art, in Paris. This article examines the powerful role that museums played in constructing national art-historical narratives during the 1930s. It argues that the intertwining of art, political diplomacy, and canon formation uncovered by an analysis of the exhibition reveals American art’s unique role in supporting shared 1930s cultural ideologies. It questions how Three Centuries of American Art located and presented the heterogeneity of American culture in the 1930s to an international audience grappling with political instability. MoMA’s curators created the most comprehensive exhibition to date of the history of American art with works from 1590 through 1938, and with over five hundred architectural models, drawings, films, paintings, photographs, prints, sculptures, and vernacular artworks. It argues that each of these successive actions—borrowing, display, canonization, publication, and reception—vested this artwork with additional, and at times, contradictory meanings that problematize our understanding of not just this exhibition’s artworks but also other exhibitions that create histories of American art. With World War II on the horizon, these artworks took on new meaning as the embodiment of the United States.