["Business Strategy and the Environment, EarlyView. ", "\nABSTRACT\nThis study examines whether board governance structures influence climate governance effectiveness and climate transition performance and whether sustainability committees reinforce these relationships. Using panel data for 5378 firms across Asia, Europe and North America (2015–2024), the analysis links board characteristics to both governance quality and carbon‐based outcomes. The results show that independent and gender‐diverse boards are associated with stronger climate governance effectiveness, lower carbon intensity and higher emissions reduction rates, while CEO duality is linked to weaker outcomes. Sustainability committees strengthen the relationship between board structures and transition performance, indicating that formalised oversight enhances the translation of governance architecture into substantive decarbonisation. These findings are robust to dynamic panel estimation and matching techniques. By moving beyond disclosure proxies to objective emissions measures, the study provides evidence that board governance plays a critical role in shaping credible corporate climate transition.\n"]