Academic medical centers across the United States stand at a moral crossroads: while excelling at sophisticated medical care within their walls, most fail to address pressing health needs in their own backyards. Through an examination of Montefiore Medical Center's comprehensive community initiatives in the Bronx, a compelling case emerges for expanding the traditional triple mission of academic medicine—patient care, education, and research—to include community service as an essential fourth pillar. Using Montefiore as a primary case study, the analysis explores how academic medical centers can successfully tackle complex social determinants of health through targeted interventions including community health centers, lead poisoning prevention programs, child protection services, housing rehabilitation, and mobile health clinics for homeless populations. The center's innovative financing approaches, particularly its "mission tax" on managed care premiums, demonstrate sustainable funding models for community health initiatives within competitive healthcare markets. While the nation's 126 academic medical centers possess extraordinary resources and capabilities to address societal health challenges, actualizing this potential demands both an unwavering commitment to community partnership and creative solutions to funding public health goods. Montefiore's experience illuminates a viable path forward for academic medical centers to truly serve as their "brother's keeper" in addressing persistent health disparities.