Purpose: To evaluate the effectiveness of a teacher-facilitated digital parenting program—the Chinese version of Parenting for Lifelong Health for Young Children (PLH-YC)—on enhancing parents’ positive parenting and reducing harsh discipline, and to examine factors influencing its effectiveness. Method: Eighty-three classes in nine kindergartens were assigned to the digital PLH-YC intervention (43 classes, 1,034 parents) or the wait-list control (40 classes, 1,039 parents). Cluster-level mixed-effects models assessed outcomes. Results: The intervention group reported significantly improvements in positive parent–child interactions and parenting practices compared to the control. No significant between-group differences were observed in violent parenting practices or attitudes towards corporal punishment. Effectiveness was moderated by school location, with rural kindergartens showing greater gains in parent–child interaction and county kindergartens exhibiting larger reductions in violent discipline. Conclusion: A teacher-facilitated digital parenting program delivered via kindergartens is a low-cost, scalable approach to strengthening positive parenting in Chinese families, with particularly strong effects in resource-limited settings.