Organizational legitimacy is essential for effective crisis governance. This study analyzes the rapid erosion of legitimacy faced by the German State Office for Health and Social Affairs (LAGeSo) during the 2015 refugee crisis, triggering cascading failures in public service delivery. Analyzing news articles and press statements, the study traces stakeholders' interactions with the LAGeSo, reconstructing key events and reactions to identify critical public governance failures. The findings show that a lack of network governance and anticipatory leadership contributed to a self-reinforcing process of legitimacy erosion, which culminated in organizational collapse. The case demonstrates that public sector crisis management requires more than technical responses; it demands strategic awareness of legitimacy dynamics and strong leadership in network governance. Adopting a legitimacy-as-process perspective, the study provides novel conceptual and practical insights for improving public crisis governance.