Improving people’s life satisfaction has become an important goal for many individuals and societies. In this study we investigate how grit influences life satisfaction. We propose that individuals’ self-esteem mediates the relationship between grit and life satisfaction. Study 1, with a sample of 243 employees enrolled in a business training course, found that an individual’s grit was positively related to life satisfaction and that self-esteem fully mediated this relationship. In Study 2, with 218 full-time employees, self-efficacy, self-control, and self-consciousness were included as mediators, but they did not exceed the power of self-esteem in explaining the relationship between grit and life satisfaction. Implications, limitations and future research directions are discussed.