["Corporate Social Responsibility and Environmental Management, EarlyView. ", "\nABSTRACT\nEmployee sustainability teams—groups collaborating continuously and voluntarily on sustainability initiatives—can serve as a bottom‐up driver for organizational change. Despite their potential, however, their role and contributions are underexplored. To fill this gap, our multi‐case study examines 59 projects by 13 teams across three companies to investigate how employee sustainability teams differ, what projects they initiate, and how organizations can promote their engagement. We introduce a morphological box to categorize team configurations, identifying two lead patterns: grassroots and formally endorsed teams. Projects differ in stakeholder focus (internal vs. external) and business impact (direct vs. indirect), which we categorize into four domains. Furthermore, we discuss organizational enablers and underscore the necessity for companies, particularly sustainability departments, to clarify these teams' roles to improve effectiveness and avoid unmet expectations. Lastly, we explore the multi‐objective nature of employee sustainability teams, outlining trade‐offs between organizational and employee goals.\n"]