Employee engagement develops positive attitudes towards the organization among employees. According to the researchers' knowledge, no investigation focused on investigating the mediating relationship of employee engagement between high-performance work practices, religiosity, personal character, leadership and work-family life balance, and job performance in the banking sector. Two hundred managers were randomly selected from banks in Sri Lanka and collected data using an online structured questionnaire. The results showed a mediating relationship of employee engagement between high-performance work practices, religiosity, and Job performance. The findings of this study add new knowledge to system theory and are essential for the policymakers and practionnaires to improve job performance in the banking sector. This study explores the relationship between high-performance work practices, religiosity, personal character, leadership and work-family life balance, and job performance and the mediating impact of employee engagement on the relationship between the variables in the banking sector. This study confirms the questionnaire's reliability and validity and adopts a partial least squares modeling method to examine the relationship. Our findings provided empirical evidence for the hypothesized relationships between employee engagement as a mediator between high-performance work practices, religiosity, and job performance. Our research findings have implications for policymakers and banking sector companies. Initially, it is essential to consider by policymakers such as the central bank Security Exchange Commission to introduce policies to improve high-performance work practices to improve job performance through employee engagement. In addition, Bank authorities should consider adopting religiosity and high-performance practices to improve job performance, which is essential to achieving higher organizational performance. The study's findings should be viewed in light of the study's limitations, which could open up a new research direction. Despite its usefulness in establishing the directional relationships among variables, cross-sectional surveying has limitations in drawing causal judgments. Future research can track the mediating relationship of employee engagement between religiousity and high-performance work practices over time using a longitudinal methodology. In addition, future researchers can establish a relationship with other sectors such as manufacturing, hospitality, plantations, etc, to generalize the results.