With growing recognition of the adverse health impacts of unmet social needs, Medicaid managed care organizations (MMCOs) are increasingly focusing on addressing the social needs of Medicaid enrollees as part of a holistic approach to care. Information and knowledge sharing among MMCOs pertaining to lessons learned and promising practices from their social determinants of health (SDOH) targeted efforts can help identify successful practical approaches for navigating common challenges, developing robust SDOH programming, and effectively delivering whole-person care. Using data from interviews with 28 representatives of 8 national and regional MMCOs, this qualitative study describes the perspectives of MMCO representatives on the lessons learned and emerging promising practices from addressing SDOH among their Medicaid enrollees. Participants discussed the importance of member and community-centeredness, structured programming, and delivery system realignment in the effective delivery of whole person care. Ten lessons learned and emerging promising practices are discussed. Findings from this study suggest that success in addressing the social needs of Medicaid beneficiaries may be achieved through adaptive, data-driven, member- and community-centric efforts by MMCOs, facilitated by system-level changes that formally integrate social services within health care. Lessons learned and promising practices can serve as a foundation for identifying and evaluating best practices and guidelines for effective MMCOs' SDOH-related programming.