One Size Still Does Not Fit All: Configuration Pathways of Environmental, Social, and Governance and Board Diversities for Higher Firm Performances Across One‐ and Two‐Tier Systems

ABSTRACT There is an ongoing, albeit uncertain, debate among stakeholders regarding the benefits of environmental, social, and governance (ESG) reporting, reflected in mixed empirical findings on its impact on firm performance. In addition to this reporting, diversity (gender and cultural) on boards, which is strongly promoted at the EU level, has gained increasing importance. However, prior research offers inconsistent results and leaves significant shortcomings regarding how the interaction of this diversity with the ESG pillars affects firm performance across governance structures. This study employs a fuzzy‐set qualitative comparative analysis and Refinitiv Eikon data of 554 European Union companies from 2023 to examine configuration pathways that combine gender and cultural diversity with ESG pillars, thus influencing firm performance across different governance forms. Drawing on Upper Echelons and Contingency Theories—enhanced by insights from Resource Dependence and Social Identity Theory lenses—we show that configurations combining gender and cultural diversity with the social pillar of ESG are linked to higher performance within one‐tier firms. In two‐tier firms, this higher performance is driven by environmental and social ESG pillars combined with cultural diversity. Recognizing that there is no single governance structure in the ESG and diversity context, we offer practitioners guidance on aligning ESG and diversity strategies with their governance architectures, developing governance‐sensitive policies, increasing transparency in diversity integration, promoting ESG competency training, and providing targeted incentives.