The current study aimed to scrutinize roles of work engagement as a mediator in the relationships between job and personal resources and employees’ outcomes, namely job performance and turnover intention, specifically focusing on testing the essentiality of work engagement. A total of 571 complete responses from full-time employees in Korean organizations were utilized for data analysis with structural equation modeling (SEM). This study analyzed two research models through the competing model approach: One model (Model 1) specified that job and personal resources directly influence job performance and turnover intention and also indirectly influence job performance and turnover intention through work engagement, whereas the other model (Model 2) specified that job and personal resources only indirectly influence turnover intention and job performance through work engagement. The results of the competing models demonstrated that overall, Model 2 adequately fit better than Model 1. The results also showed that the direct effects of job and personal resources on work engagement, as well as the direct effects of work engagement on job performance and turnover intention were statistically significant. In addition, the results of the study revealed statistically significant mediating effects of work engagement, not only on the relationship between job and personal resources and job performance, but also on the relationship between job and personal resources and turnover intention. Based on the results, theoretical and practical implications for human resource management, limitations, and recommendations for further research are discussed.