The purpose of this study is to investigate the influence of pre-service early childhood teachers academic self-efficacy and grit on happiness. For this purpose, 300 Pre-service early childhood teachers in preschool education at universities located in Busan, Ulsan and Gyeongsangnam province were randomly sampled and selected. In order to measure the pre-service early childhood teachers academic self-efficacy, I used the academic self-efficacy test tool modified by Kim Byung-man, Kim Jung-ju and Youn Jung-jin (2017) after the development and validation of Kim Ae-Young and Park In-Young (2001). The original Grit Scale (Grit-O) developed by Duckworth, Peterson, Matthews and Kelly (2007) was used to measure grit. And to measure happiness, we used the multidimensional happiness scale developed by Butler and Kern (2014) and developed by Kim Mi-jin (2015) based on the PERMA theory of wellness in Seligman (2011). The results of this study are as follows. First, as a result of pre-service early childhood teachers perception of academic self-efficacy, grit, and happiness, positive perceptions were more than usual in all variables. Second, there is a significant positive correlation between the pre-service teacher s academic self-efficacy, grit, and happiness. Third, the academic self-efficacy of pre-service early childhood teachers was a factor affecting the happiness of pre-service early childhood teachers. Specifically, it was found that task difficulty preference, self-regulated efficacy, and self-confidence affect the happiness of pre-service early childhood teachers among the sub-variables of happiness. However, the sub-variables of Grit did not affect the pre-service teachers happiness.