Environmental sustainability in company operations has garnered attention recently. Environmental management companies may benefit from being the first to apply new tactics and boost their green image. Therefore, global banking management considers green banking the most important environmental management tool. Hence, Bangladesh’s banking industry is developing green banking practices in response to the government’s urge. Accordingly, employee green behavior (EGB) helps banking organizations maximize their green potential. Thus, promoting EGB has been difficult for practitioners. Hence, this study offered a new paradigm and examined how green training (GT) and green perceived organizational support (GPOS) affect EGB using social exchange theory (SET). The study also examined how green knowledge sharing (GKS) mediates the correlations. This study surveyed 326 frontline employees of a full-time Bangladeshi bank using a questionnaire. Partial least-squares structural equation modeling (PLS-SEM-4.1.1) was used to investigate the assumptions. The findings of the study reveal that GT and GPOS favorably affect EGB. The outcomes also showed that GKS mediates the proposed relationships. The findings allow Bangladesh’s banking industry researchers and practitioners to promote green behavior among frontline employees.