This study examined the effects of salespersons' happiness on burnout as mediated by mindfulness and emotional intelligence. The research model was established based on the broaden-and-build theory of positive emotions. According to this theory, positive emotions such as joy, love, and gratitude broaden the scope of conscious activity, which in turn leads to increases in psychological, social, and physical resources, thereby improving performance across all areas of daily life and consequently enabling individuals to experience higher levels of happiness than at present. Meanwhile, mindfulness refers to a state or disposition of non-judgmentally accepting and paying focused attention to experiences occurring both inside and outside the body, and prior research has established it as a personal asset capable of ameliorating negative psychological states such as stress and anxiety. Six hypotheses were formulated regarding the relationships among happiness, mindfulness, emotional intelligence, and burnout, and a survey was conducted among salespersons. Covariance structure analysis of 224 survey responses revealed that all five hypotheses were supported except for the effect of emotional intelligence on burnout. Specifically, happiness influenced burnout in a mitigating direction, both directly and through mindfulness. Moreover, this influence was more pronounced through the indirect path via mindfulness than through the direct path. Furthermore, happiness and mindfulness were found to have a positive effect on emotional intelligence. This study stands in contrast to the prevailing perspective in management studies, which has focused on eliminating negative deficiencies, in that it utilized findings from the positive psychology movement, which assumes high human potential. Additionally, through this study, the need for educational programs that enable individuals to experience positive emotions more frequently and enhance their level of mindfulness was identified.