Research has underscored the agenda-setting and policy implementation advantages associated with the concentration of political and policy-making authority. But to what extent does this concentration of authority within health policy-making institutions determine the early timing and depth of non-communicable disease (NCD) policies? Are other factors within and outside of government more important? Comparing one Latin American country exhibiting a strong concentration of political and policy-making authority, Mexico, to one that does not, Brazil, we find that weaker, fragmented political and policy-making powers in Brazil expedited the creation and implementation of NCD programs. As seen in Brazil, our findings suggest that the factors that account for the earlier adoption of NCD policies and successful implementation are the early institutionalisation of societal interests and pressures within the bureaucracy, the “bottom-up” diffusion of early policy ideas, and international policy recommendations. This institutional, participatory, and ideational approach may provide more important predictors for explaining variation in NCD policies.