We review the ambiguous legacy of Emil Kraepelin. He established an approach that secured psychiatry’s place as a medical specialty, and his methodology has dominated the profession and defined its long 20th century, 1899–2026. However, his eugenic views weigh heavily because of the catastrophes in which German psychiatry was implicated and to which it contributed actively during the Nazi era that followed. Furthermore, his project to establish mental illness in the form of discrete natural kinds has failed in the light of scientific progress. Psychiatry must embrace the complexity of mental illness and engage more deeply with the inherently fuzzy realms of language, culture, technological change and political power. This shift should bear more strongly on psychiatry’s curriculum, research priorities, continuing professional development, practice, ethics and public engagement.