Previous studies have revealed the association between work-family balance and job satisfaction. The present research further explored the underlying mechanism of this association and aimed to provide a moderated mediation model to explain if personality traits moderate the relationship between work-family balance and job satisfaction through work engagement. A cross-sectional study was conducted in which 263 employees from a petrochemical enterprise in China completed self-report questionnaires including the Work-Family Balance Scale, the Utrecht Work Engagement Scale, the Big Five Inventory-10, and the Job Satisfaction Scale. Hierarchical regression analysis and structural equation modeling showed that work engagement partially mediated the relationship between work-family balance and job satisfaction, and the indirect effect was further moderated only by extraversion. Therefore, an integrative moderated mediation model was proposed wherein work-family balance boosts job satisfaction by first enhancing employees' work engagement, while the indirect effect was in turn moderated by extraversion. The results suggest that interventions for improving job satisfaction may be enhanced by targeting work engagement, especially for employees with higher extraversion.