This study examined the structural relationship among children’s grit, self-esteem, and life satisfaction. We analyzed the data of 2,607 4th graders (1,313 males and 1,294 females) from the 2018 Korean Children and Youth Panel Survey (KCYPS). A structural equation model was used to verify the model, and a bootstrap approach was used to assess the mediating effect of self-esteem. As a result of the study, first, we found that grit had a direct effect on self-esteem. Second, we found that self-esteem had a direct effect on life satisfaction. Third, we found that grit had a direct effect on life satisfaction. Fourth, self-esteem mediated the effect of grit on life satisfaction. This study is meaningful because it helps in understanding the factors that predict children’s life satisfaction.