The purpose of this study was to find out the mediation effect of psychological burnout between the relationship between emotional labor and job engagement. Also, this study verified the moderating effect of “length of service” on the mediation effect of psychological burnout. A survey was conducted to 114 beauty-related non-benefit hospital medical service personnel working in Seoul, Gyeonggi, Chungbuk, and Chungnam province. First, descriptive statistics and correlation between variables were examined. Next, the PROCESS Macro of Hayes(2013) was conducted to verify the moderated mediation effect. Psychological burnout was entered as a mediator variable, and length of service was included as a moderator variable in the relationship between emotional labor and job engagement. The results of this study are as follows. First, emotional labor had a positive correlation with psychological burnout. On the other hand, emotional labor and psychological burnout were both negatively related to job engagement. Second, psychological burnout was found to fully mediate the relationship between emotional labor and job engagement. Third, the length of service moderated the relationship between psychological burnout and job engagement and a significant moderated mediation effect was found in the whole model. Implications for individual and organizational intervention plans and limitations were discussed based on the results of the study.