In service industries such as restaurants, abusive customer (jay-customer) behaviors may evoke emotional exhaustion and burnout in frontline employees, threatening job satisfaction as well as sustainable management in the hospitality industry. Therefore, there is a need to identify whether (and to what degree) such customer behaviors stress frontline employees enough to affect their mental health, which may lead to employee turnover. To understand jay-customer behaviors in a restaurant setting, this study investigated the factors of jay-customer behaviors that induce job stress and decrease job satisfaction. Additionally, the moderating effect of empowerment was tested to see whether employee empowerment decreases the stress caused by jay-customer behaviors. Data collected from 302 restaurant employees from several cities in South Korea were analyzed using exploratory factor analysis and structural equation modeling. The study results demonstrate that three types of jay-customer behaviors (verbal abuse, physical abuse, and sexual harassment) are directly related to frontline employees’ job stress, which in turn, reduces job satisfaction. A moderating effect of empowerment on the relationship between verbal abuse and job stress is found. The results of this study suggest a conceptual model for understanding the process in which jay-customers negatively influence the frontline employees, threatening employee well-being, and they provide valuable implications for the restaurant industry, which can help develop strategies to improve employee welfare and provide better customer management.