Employees’ beliefs about justice were found to be related to positive work attitudes and behaviors. We complement this line of research by focusing on whether justice beliefs benefit employees by increasing their career success. Drawing on the just world hypothesis, this study explores the impact of personal belief in a just world on employees’ subjective and objective career success and considers the mediating mechanism of work engagement in this association. Three-wave time-lagged data from 320 full-time employees in China supported our hypothesized mediation model. Our research underlines the importance of employees’ justice beliefs for their career development and satisfaction, and suggests that organizations should avoid unjust experiences to increase employees’ work engagement, and furthermore benefit their career success.