["Business Strategy and the Environment, EarlyView. ", "\nABSTRACT\nFirms are under increasing pressure from regulators, investors, and civil society to appoint specialist directors with expertise in areas such as climate change, cybersecurity, and diversity. While specialists can strengthen oversight, boards dominated by them may risk authority bias, symbolic appointments, and narrower strategic focus. This study examines whether nonspecialist directors, those with broader managerial experience rather than narrow technical expertise, play a complementary role in advancing environmental innovation. Drawing on the resource‐based view, we argue that nonspecialists contribute integrative human and relational capital that fosters strategic flexibility and broad‐based problem solving. Using panel data on firms from Australia, the United Kingdom, and the United States (2007–2021), we find that a higher proportion of nonspecialists is positively associated with environmental innovation. This effect is amplified in firms with governance committees, environmental management teams, and active strategic investors. By highlighting the value of balancing specialist and nonspecialist expertise, this study contributes to corporate governance and sustainability research and offers actionable insights for boards seeking to align governance with environmental performance.\n"]