Although recent English-language Vietnam War scholarship has devoted considerable attention to reassessing the Ngô Đình Diệm era, contemporaneous South Vietnamese interpretations of the president’s tenure have been largely overlooked. Contrary to prevailing assumptions that his influence ended abruptly with his 1963 murder, Ngô Đình Diệm was a hotly debated figure long after his death. Moreover, his contested legacy came to symbolize South Vietnam’s enduring political, regional and religious schisms, contributing to and reinforcing his country’s profound social fragmentation. The fluid and ambiguous memory that Vietnamese had of his time in office had a substantial impact on subsequent political developments, establishing patterned dynamics of political conflict that endured throughout the Second Republic and providing conceptual yardsticks against which subsequent politicians and political developments were measured. Ngô Đình Diệm’s fraught symbolic resonance and significant posthumous political impact are therefore crucial dimensions to consider in evaluating his legacy.