In this study, we examine how climatic heat stress can be mediated by green infrastructure outcomes and how energy justice effort contributes to health adaptation within the U.S. Great Lakes regions and their primary metropolitan areas over a recent 10-year period (2005–2015). Through the lens of policy innovation and the vulnerability-readiness nexus, we explore how climate policy intervention contributes to the mitigation of heat stress by using a quantitative approach. Empirical results suggest that green infrastructure outcomes and energy justice efforts have the potential to mitigate heat stress and enhance health adaptation. Additional results reflect that climate policy innovation and readiness efforts were viable factors in health adaptation to heat events.