The purpose of this study is to investigate the relationship between transformational leadership (TL) and change-oriented organizational citizenship behavior (OCB) based on basic assumptions of the job demand-resource (JD-R) model, social exchange theory (SET), and behavioral plasticity theory (BPT). In addition, this study explores the role of the organizational level of resources and individual level of resources on employee wellbeing and attitudes. Based on 698 responses from Jordanian insurance employees, the mediating role of employee wellbeing and the moderating role of core self-evaluation (CSE) were investigated between TL and change-oriented OCB. Data were analyzed based on multiple regression, hierarchical regression, and macro process plugin. The results indicate that transformational leadership is positively related to change-oriented OCB, and this relationship is mediated by employee wellbeing. Moreover, moderated path analysis shows that the positive CSE strengthens the direct effect of TL on employee wellbeing and work attitude, as well as the indirect impact of TL on employee work attitude. The results also suggest that organizational level of support is a critical factor for enhancing employee wellbeing and change-oriented OCB, and this support is more powerful with a high level of personal resources (i.e., positive CSE). The research model provided in this study is the first framework that suggests the mediating effect of employee wellbeing on the direct relationship between TL and change-oriented OCB, as well as the moderating effect of CSE on this indirect relationship.