In this final paper in a five-part series highlighting the opportunities for integrating mental health care into priority global health programs and platforms of health service delivery, we aim to synthesize the evidence presented in the articles in the series addressing maternal health, non-communicable diseases (NCD), and HIV/AIDS care, with the goal of identifying overarching themes across these platforms. Our focus is on competencies and work packages appropriate for health care settings that do not historically address mental health issues and that do not usually include mental health specialists. Primary health care is the quintessential example of such a care delivery platform. In this paper, we consider the rationale for integration, the extent to which specific mental disorders can be addressed in other delivery platforms (and, the corollary, which disorders may need a more specialized approach to care), the process of integration, potential risks and barriers to successful integration and strategies how these might be addressed, and the promise of this approach for addressing the leading Grand Challenges in Global Mental Health.