Objectives: This research investigates how mother-child interactions mediate the effect of employed mothers' work-family balance on their children's excessive smartphone use. The study aims to provide insights for developing support for working mothers and their children.Methods: A questionnaire was distributed to employed mothers with children in kindergartens and daycare centers in Seoul and Gyeonggi, yielding 221 valid responses. SPSS 26.0 and Mplus 7.4 were used for analysis, including frequency analysis, descriptive statistics, confirmatory factor analysis, and a mixed structural equation model, with significance at α = .05 and a 95% confidence interval.Results: The study found that a positive work-family balance enhances mother-child interaction, which in turn reduces children's smartphone overdependence. Conversely, work-family conflict increases this dependence, but is mitigated by mother-child interaction. The study delineates the relationships among work-family balance, interaction, and smartphone dependence in children.Conclusion: The interaction between working mothers and their children significantly influences children's smartphone overdependence. Thus, it's crucial to support employed mothers through educational strategies and programs promoting quality interactions with children, balancing work and family roles.