Sustainable Human Resource Management (HRM) represents a new approach to managing human resources, seeking to reconcile the relationship between HRM practice and achievements beyond financial metrics. However, there is little integrative research examining the multifaceted determinants of sustainable HRM. Based on institutional theory and upper echelons theory, we advance a multilevel argument that challenges prevailing explanations regarding an organization’s single driver to implement a specific HRM system. Employing a configurational approach, we investigate how six antecedents encompassing external and internal organizational factors shape the landscape of sustainable HRM. There emerge three configurations facilitating highly sustainable HRM and two configurations leading to non-highly sustainable HRM. In the case of highly sustainable HRM, the three antecedents external to the organization—government regulation, public service, and innovative environment—synergistically complement one another. Conversely, the three factors within the internal organizational environment—organizational governance structure, sustainability strategy, and executives’ sustainability perception—show substitutional relationships. Additional analyses further revealed two configurations resulting in not-highly sustainable HRM. Theoretical and managerial implications are discussed.