Background: Teachers' professional commitment is essential for providing high-quality early care and education (ECE) to young children. Previous studies suggest that teachers' perceptions of low levels of personal stress and a satisfactory work environment are both likely to be associated with their greater commitment to work. Objective: The current study examined the incremental validity of work environment as a predictor of professional commitment beyond personal stress perceived by ECE teachers in South Korea. Specifically, we hypothesized that teachers' satisfactory work environment would predict a significant amount of variance in professional commitment beyond personal stress. Methods: Survey data were collected from 322 ECE teachers in center-based programs in Korea. Confirmatory factor analysis (CFA) was used to examine the factor structure of the professional commitment latent variable. Hierarchical regression models were tested in structural equation modeling with the professional commitment latent variable. Results: CFA for professional commitment demonstrated that a one-factor model was the best solution. The final model explained 40% of the variance in professional commitment (RMSEA = 0.067; CFI = 0.906). Findings indicated the incremental validity of work environment in predicting professional commitment beyond personal stress. Conclusions: The current findings emphasize the importance of teachers' experiences around having a satisfactory work environment and personal stress, either job-related or not, to retain teachers in ECE settings long-term. Program and policy level support to promote teachers' well-being in their personal lives as well as professional lives may be critical to improve teachers' professional commitment.