The purpose of this study is to investigate the mediating effect of infant teachers’ flourishing on the influence of home daycare center organizational health on infant teachers’ professionalism. Data were collected through electronic and paper surveys from 236 infant teachers working at home daycare centers in Gyeonggi-do. The data were analyzed using SPSS 25.0 and the Process macro-statistical program and included frequency analysis, descriptive statistical analysis, correlation analysis, hierarchical regression analysis, and mediation analysis. The main results are as follows. Firstly, there is a significant correlation between the organizational health of home daycare centers and all sub-factors of infant teachers’ professionalism, as well as flourishing. Secondly, it was confirmed that flourishing partially mediates the influence of home daycare center organizational health on infant teachers’ professionalism. Therefore, when the organizational health of a home daycare center improves, it is observed that infant teachers increased positive emotions, engagement, meaning, relationships, achievement, and physical health, leading to the manifestation of flourishing. Consequently, this contributes to the enhancement of infant teachers’ professionalism. These results are expected to be utilized as foundational data for the development of programs aimed at improving the professionalism of infant teachers and enhancing the organizational health of home daycare centers.