Physicians who choose to serve in public sector mental healthcare settings and physicians-in-training assigned to public sector mental health clinics may not be fully prepared for the many roles of the public and community psychiatrist. This primer offers practical information and guidance to the psychiatrist called upon to serve in the roles of public-sector clinician, team member, advocate, administrator, and academician. Each chapter includes a concise description of these various roles and responsibilities and offers engaging examples of the public psychiatrist at work. The chapters also ask readers to thoughtfully consider case-based problems typical of those faced by the public psychiatrist. Each chapter also features works of art and literature, usually from the public domain. Medical humanities help physicians keep sight of the lived experiences of public-sector patients; this includes not only the pain and suffering endured by them due to both the medical disorders with which they live and the disparities they endure in health, educational and occupational outcomes, but also their resilience while facing so many challenges. Medical humanities also serve to reinforce the physician’s individual and collective will to address the disparities endured by our patients. There are several very comprehensive textbooks available that examine community psychiatry broadly. By contrast, this work is a concise guide for the resident and early-career psychiatrist to the many roles he or she might be asked to provide in a public-sector mental health setting. Our hope is that the primer provides a level of support to psychiatrists that fosters their desire, individually and collectively, to serve the poor and the marginalized with grit and determination, and to broadly consider their potential to improve not only patient well-being but also these patients’ incorporation into their communities.