Employment has an enormous impact on the livelihood of employees with disabilities (EWDs). There have been many barriers to EWDs being hired in hospitality businesses. Therefore, the research presented in this thesis aimed to examine the job performance of frontline EWDs when they directly interacted with customers. While there are many approaches to the evaluation of job performance, my research focused on the quality of the service interaction quality (IQ) between EWDs and customers as a key indicator. More importantly, this study identified the major individual and organizational drivers of EWDs’ job performance and examined how these drivers influenced the service IQ evaluated by customers. Personally, I, by this doctoral research, hoped to provide an opportunity for EWDs in the Vietnamese hospitality industry to speak out and express their opinions about job performance when interacting with customers. To achieve the research objectives mentioned above, I used the mixed-methods approach as the methodology. The study included two sequential qualitative and quantitative phases. For Phase 1, semi-structured interviews were conducted with frontline EWDs and customers at cafés and restaurants in four major tourist cities in Vietnam (Ho Chi Minh City, Da Nang, Hoi An, and Ha Noi). As the literature about job performance of EWDs is limited, the qualitative phase aimed to determine the major individual and organizational drivers influencing the job performance of EWDs. In Phase 2, a paper-based survey with EWDs and their customers was conducted on a larger scale in Vietnam. The objectives of Phase 2 were to examine the effects of major individual and organizational drivers on immediate outcomes including organizational commitment and perceived organizational support and the service IQ between EWDs and their customers. Furthermore, the study tested the hypotheses of organizational tenure as a moderator of the links between the drivers and the immediate outcomes. The results were expected to establish the theoretical framework of the job performance of EWDs when they interacted with customers. From these two phases, qualitative and quantitative, the unique data from interviews and surveys provided significant insights for analysis and for drawing conclusions from the findings. The interviews with EWDs in Phase 1 revealed that agreeableness (being friendly, collaborative), a proactive personality (being attentive and actively providing delightful service) and support from leaders (leadership and training activities) were the major individual and organizational drivers influencing the job performance of EWDs. The results of Phase 2 showed that all four major drivers of the job performance of EWDs had a significant influence on the service IQ. Two immediate outcomes, namely organizational commitment and perceived organizational support had mediating effects on the relationships between drivers and the service IQ. In addition, this research found that organizational tenure moderated the effects of organizational drivers on the immediate outcomes – as such, the effects of organizational drivers were stronger for EWDs with longer tenure than those with less tenure. Through the process of collecting and analysing the data in drawing the conclusions, the study provided many profound research and practical implications. This doctoral research has significant methodological implications as it empowered the voices of EWDs and integrated the customer perspective in the dyadic approach. Thus, the data obtained in this study is valuable for understanding the job performance of EWDs. In addition, this doctoral research developed a conceptual framework which demonstrates the effects of major individual and organizational drivers on the service IQ and the influences of the mediators and moderators. This framework is a meaningful contribution to the literature of human resource management in the hospitality context. I have also provided practical suggestions for hospitality practitioners, including EWDs and managers, to enhance job performance in the process of service delivery.