Extreme heat events have rapidly increased over the last several decades and is a leading cause of health threats in cities and communities worldwide. Despite the seriousness of this situation, urban planning scholars have yet to sufficiently examine the multidimensional nature of health risk to extreme heat in the scope of the built environment. Furthermore, literature that empirically explores relationships between extreme heat scenarios and road safety in cities is scant. This dissertation research focuses on the intersection of extreme urban heat, public health risk, and the built environment; it presents three interconnected and standalone studies. To synthesize what we know to date on how heat-related risks and associated health outcomes manifest in urban planning and the built environment, this study systematically reviewed urban areas’ extreme heat and health mortality and morbidity. The literature review used empirical evidence drawn from refereed manuscripts to bring attention to the built environment factors that are significant but understudied public health threats in times of extreme heat events. The review highlighted the linkages that have been least explored and/or in the germane literature and expatiated on key challenges in conducting research on associations between extreme heat and health risk in the context of urban environment. The first empirical study applied latent variable analysis analytics to explore the dimensionality of health risk associated with extreme heat by integrating a wide range of data sets from multiple disciplines, including but not limited to public health, applied geography, environmental science, and urban planning. Socioeconomic and socioenvironmental factors related to extreme heat are examined altogether with human behavioral risk factors in the dimensionality analysis. The final empirical piece examines the relationship between extreme hot days and non-motorized traffic crashes from a spatiotemporal perspective. Using a series of spatial econometric approaches, I found significant associations between extreme hot days and both the occurrence and severity of non-motorized crashes. I suggest that future research needs to adopt a dynamic traffic risk management approach that considers both urban climate and spatial dependencies when making transportation safety management plans. This dissertation is the first attempt to utilize latent variable analysis technique in a more sophisticated way to explore the dimensionality of health risk to extreme heat and the underlying factors resulting in different degrees of health risk associated with heat. It is also the first trial to quantify the spatiotemporal relationship between heat extremes and the mobility exposure and consequences, i.e., non-motorized traffic crashes.