Understanding predictors and effects of teacher well-being, including job satisfaction, is crucial for both teachers' and children's development. Research on teacher job satisfaction (TJS) has indicated that many individual and contextual factors may make a difference for teachers' professional well-being. However, against the backdrop of this larger literature, relatively less attention has been paid to kindergarten teachers, despite the pivotal importance of this transition to grade school on children's long-term academic success. In this study, we first employed confirmatory factor analysis to validate the construct of TJS and then used structural equation modeling to investigate the specific predictors of kindergarten TJS (e.g., job resources, job demands, teacher job self-efficacy). Finally, we used structural equation modeling again to examine the relations between TJS and kindergarten children's academic and social development. We used the Early Childhood Longitudinal Studies--Kindergarten, a nationally representative dataset including American children who began kindergarten in 2011. Results shed light on the complex phenomenon of TJS in this critical school transition period.