Social Determinants Accelerator Act of 2021 This bill establishes the Social Determinants Accelerator Interagency Council and a grant program to address social determinants of health. These are nonmedical factors that influence health outcomes, such as income, educational attainment, and place of residence. Specifically, the bill establishes the council, comprised of federal and nonfederal members, to increase coordination among health and social service programs and provide technical assistance to increase the impact of such programs. In consultation with the council, the Department of Health and Human Services must award up to 25 grants to state, tribal, territorial, or local health agencies, certain nongovernmental entities, or consortia of entities (which must include a health agency) for social determinants accelerator plans. These plans must address at least one health and one social outcome for a specified target population.