The escalating impacts of climate change have intensified extreme weather patterns, producing scorching summers and severe winters across many regions of the United States. These shifts not only drive higher building energy consumption but also degrade outdoor thermal comfort, undermining efforts to foster socially engaging neighborhood environments. This research responds to the pressing need to reconsider residential development by optimizing building morphology to balance energy efficiency and outdoor comfort. Although the vision of socially vibrant neighborhoods has long been pursued, harsh climates diminish outdoor livability while simultaneously straining indoor comfort and energy demand. To address this challenge, the study emphasizes the strategic application of building block forms, integrating advanced simulation and analytical tools—ENVI-met, DesignBuilder, BEopt™, and RayMan—to optimize both individual buildings and neighborhood-scale morphology. The thesis investigates the thermal and energy performance of various low-rise residential development patterns in both hot and cold U.S. climate regions, aiming to support indoor thermal comfort while also enhancing outdoor environmental quality for residents. The inquiry is structured around two central research questions: (1) To what extent can building development morphology improve thermal comfort and energy efficiency in low-rise residential buildings? (2) What specific morphological features contribute most to these improvements in harsh climates? To answer these, the study adopts a multi-method approach, including a review of literature on block morphology and thermal comfort standards, parametric analyses of building and block forms using DesignBuilder and BEopt™, field measurements for model validation, and case studies of neighborhood microclimates in hot and cold climates assessed with ENVI-met and RayMan. The ultimate goal is to propose a holistic framework for neighborhood design in diverse climates, advancing energy efficiency and thermal resilience at both the building and block levels. The findings offer practical insights into how morphology can be harnessed to enhance thermal comfort while reducing energy use, contributing meaningful guidance for architects, planners, developers, and policymakers. By combining simulation-based research with field validation, this thesis deepens understanding of the complex relationship between urban form, thermal comfort, and energy performance, providing a foundation for resilient and socially sustainable neighborhoods in the face of climate change.