Achieving universal health coverage (UHC) involves distributing resources, especially human resources for health (HRH), to match population needs. This paper explores the policy lessons on HRH from four countries that have achieved sustained improvements in UHC: Brazil, Ghana, Mexico and Thailand. Its purpose is to inform global policy and financial commitments on HRH in support of UHC. The paper reports on country experiences using an analytical framework that examines effective coverage in relation to the availability, accessibility, acceptability and quality (AAAQ) of HRH. The AAAQ dimensions make it possible to perform tracing analysis on HRH policy actions since 1990 in the four countries of interest in relation to national trends in workforce numbers and population mortality rates. The findings inform key principles for evidence-based decision-making on HRH in support of UHC. First, HRH are critical to the expansion of health service coverage and the package of benefits; second, HRH strategies in each of the AAAQ dimensions collectively support achievements in effective coverage; and third, success is achieved through partnerships involving health and non-health actors. Facing the unprecedented health and development challenges that affect all countries and transforming HRH evidence into policy and practice must be at the heart of UHC and the post-2015 development agenda. It is a political imperative requiring national commitment and leadership to maximize the impact of available financial and human resources, and improve healthy life expectancy, with the recognition that improvements in health care are enabled by a health workforce that is fit for purpose.