This study examined the hypothesis that a medical school in a low-resource setting, based on volunteer faculty, can be sustainable and associated with improvement in medical workforce and population health outcomes. Using a retrospective case study approach, this study described the formation of the Ateneo de Zamboanga University School of Medicine (ADZU SOM) in Zamboanga province, Mindanao, Philippines. The principal outcome measures were the number of graduated students practicing as physicians in the Philippines, the number of local municipalities with doctors, and changes in the provincial infant mortality rate since the School's inception. Since the first 15 graduates in 1999, by 2011 more than 160 students had successfully graduated with over 80% practicing in the local underserved regions. This compares with a national average of 68% of Philippine medical graduates practicing overseas. There has been a 55% increase (n=20 to 31) in the number of municipalities in Zamboanga with a doctor. Since the ADZU SOM's inception in 1994, the infant mortality rate in the region has decreased by approximately 90%, compared with a national change of approximately 50% in the same time period. The School has only three employees because all teachers continue to work as volunteer clinicians from the local health services. These results can encourage governments and communities around the world to consider adopting a socially accountable approach to medical education as a cost-effective strategy to improve medical workforce in underserved areas.