Key Finding: Research from Exemplars in Global Health found that, relative to their peers, national community health worker programs in Bangladesh, Brazil, Ethiopia, and Liberia have made vital contributions to improving primary healthcare access. To achieve this success, these countries harnessed political will to mobilize government-led coordination, designed programs that respond to population needs, invested in comprehensive systems to support community health workers, cultivated community support and used data to continually refine and innovate.