Diversity, equity, and inclusion (DEI) efforts have garnered increased attention as companies recognize their potential to enhanceboth employee well-being and green performance. Based on affective event theory (AET) and social exchange theory (SET), thisresearch examines the impact of perceived firm diversity, equity, and inclusion (DEI) on employee well-being and green perfor-mance, with a focus on the moderating effect of leader emotional expression. This study specifically links DEI to environmentalmanagement by demonstrating how inclusive workplace cultures foster employee well-being, which enhances organizationalcommitment to sustainable practices, such as reducing environmental impact and achieving firm green performance. 362 UnitedStates respondents were collected, and the analysis was conducted using SmartPLS. The results indicate that perceived firm DEIhas a strong positive effect on employee well-being and green performance, including environmental outcomes. DEI increasesgreen performance by improving innovation and stakeholder engagement, aligning with sustainability targets. The outcomesindicate that the emotional expression of a positive leader enhances green performance by supporting a conducive environmentthat promotes employees to adopt sustainable practices, while negative expressions of a leader may limit this impact due to anincrease in employee resilience. The present research has numerous theoretical and practical implications, providing an expla-nation of how companies can utilize inclusive practices to support staff well-being and maximize performance, particularly inenhancing environmental sustainability, as well as identifying which leadership behaviors might enhance these advantages