The position of school principal is emotionally demanding. Principals' occupational well-being (OWB) can be influenced by their emotional work characteristics, and their emotional regulation plays a critical role. Based on the job demands-resources (JD-R) model, this study investigated the relationships between kindergarten principals' OWB and its complex antecedents. Specifically, the study examined the influences among emotional job demands and trust in colleagues on kindergarten principals' OWB factors (job satisfaction and emotional exhaustion), with a particular focus on the role of their emotion regulation strategies. Through an investigation of 618 kindergarten principals in China, the results showed that emotional job demands and trust in colleagues had different influences on principals' OWB dimensions. Emotional job demands can enhance both principals' suppression and reappraisal strategies, and trust in colleagues functions as an interpersonal resource for reappraisal. Principals' emotion regulation strategies mediated the influence of work characteristics on OWB. Reappraisal is an important personal resource that can buffer the influence of work demands on OWB. The results may extend our understanding of principals' emotional work. The implications on principals' work and emotion regulation were further discussed.