It is essential for organizations to invest and improve employee outcomes to enhance organizational competitiveness and growth in today’s world. However, most organizations place management objectives above the career competencies of employees. Therefore, this study investigated 1. the effect of high-performance work practices on employee career competencies in the banking industry. 2. the mediating effect of employee career competencies on the relationship between high-performance work practices and employee outcomes in the banking sector. The study adopted a quantitative approach with a total of 340 respondents from various banks in Tanzania. The data was analyzed using Covariance Based Structural Equation Modelling (CB-SEM). The results of the finding indicate that high-performance work practices have a significant effect on employee career competencies. Similarly, employee career competencies significantly impact service quality, creative performance, and extra-role performance in banks. Also, employee career competency does not mediate the relationship between high-performance work systems and service quality in the banking industry.