Grit, defined as perseverance of effort and consistency of interest, has attracted attention as a predictor of success in various fields beyond IQ and the Big Five personality dimension of Conscientiousness. The purpose of the current study was to examine previously uninvestigated questions regarding grit using a cross-sectional design among a large number of working adults in Japan. First, we tested geographical generalizability of associations between grit and orientations towards happiness by comparing previous studies in the U.S. and the current study in Japan. It was confirmed that orientation towards meaning rather than orientation towards engagement had a stronger positive correlation with grit in our sample of Japanese people. This result is inconsistent with previous studies in the U.S. Furthermore, the Big Five dimension of Openness to Experience was newly confirmed as having a positive association with grit. Second, we examined the association between grit and work engagement, which is considered as an outcome indicator for work performance. In this analysis, grit was a strong predictor for work performance as well as academic performance.