Although much research has examined human resource management (HRM), managers’ roles in HRM seem to have been ancillary to this area of research. That is, HRM theory and research largely has advanced with a focus on policies, practices, systems, and their implementation and effectiveness, with less attention focused on the managers responsible for the design, adoption, enactment, and implementation of HRM strategy and practice. The purpose of this review is to examine extant research to determine the state of knowledge of the role of managers across organizational hierarchy in HRM. Thus, we review empirical literature for studies that include aspects of the impact lower-to-middle managers, human resource managers, top management teams, CEOs, and boards of directors have on HRM content, process, and outcomes. On the basis of the findings of this systematic, multilevel review, we discuss avenues for future research at each specific manager’s level, as well as general opportunities and challenges for research on managers’ roles in HRM across all hierarchical levels.