Abstract Cross‐sector partnerships (XSPs) are embraced by policymakers and practitioners to address complex social and environmental challenges that no single sector can tackle alone. However, extant research on XSPs has primarily focused on isolated phases and singular theoretical perspectives. In our paper, we synthesize XSP research in the public policy and management fields to deliver a comprehensive and coherent understanding of XSPs’ different phases and theoretical perspectives – the XSP ‘theoretical topology’. We introduce two approaches for theoretical enrichment: informing and interacting. We emphasize the significance of ‘theoretical interstices’ as undominated spaces for new knowledge exploration. Through our integrative cross‐phase, cross‐theoretical approach, we address fundamental yet open questions on XSP effectiveness, value, and impact. Our work challenges existing understandings and opens new research possibilities; offers implications for practitioners; and informs current policy debates on mandating XSPs and on the role of ‘big data’ – powered algorithms in the XSP landscape.