Green organizational citizenship behavior is essential for translating corporate sustainability strategies into everyday work practices. Although green transformational leadership has been widely examined as an antecedent of employee green behavior, less is known about why it encourages employees to go beyond formal job duties and when this effect becomes stronger. Drawing on Broaden-and-Build Theory, this study develops a psychological resource model linking team-level green transformational leadership to green organizational citizenship behavior through employees’ cognitive-motivational and affective resources. Specifically, we examine general psychological empowerment (hereafter, empowerment) and environmental passion as complementary psychological resources, and leaders’ emotional intelligence (LEI), assessed through employee ratings, as a socio-emotional boundary condition. Multilevel path analysis was conducted using matched multi-source, three-wave time-lagged survey data from 517 employees nested within 77 teams in 10 Chinese new energy enterprises. The results showed that green transformational leadership was positively related to green organizational citizenship behavior. Empowerment and environmental passion mediated this relationship, while LEI strengthened both the green transformational leadership–green organizational citizenship behavior relationship and the empowerment–green organizational citizenship behavior relationship. These findings extend green leadership research by showing that a domain-specific leadership behavior can promote discretionary green behavior through both a general work-related cognitive-motivational resource and a domain-specific affective resource, and that this process becomes stronger when leaders are perceived as emotionally intelligent.