Excessive smartphone use among young children may reduce parent–child interaction, limit social activities, and potentially hinder cognitive development and diminish children’s motivation to learn. From the perspective of Vygotsky’s social constructivist theory, children’s development occurs through interaction with more knowledgeable individuals, including parents. Therefore, parental involvement is essential in guiding children’s smartphone use. This study aimed to analyze the role of filial therapy in minimizing the negative effects of smartphone use on children’s mental health and learning motivation. The study employed a quantitative approach using an analytical descriptive design focusing on causal relationships. The participants were 75 parents of Kindergarten A children aged 18–38 years. Data were collected through questionnaires using Likert-scale instruments and analyzed using the Statistical Package for the Social Sciences (SPSS). The findings indicated that the implementation of filial therapy through parental involvement and guidance contributed to minimizing the negative effects of smartphone use on children’s mental health and learning motivation. Uncontrolled smartphone use tended to reduce children’s interest in learning activities and social interaction. Thus, parental guidance through filial therapy can serve as a strategy for promoting more controlled and constructive smartphone use among young children. The findings imply that parents should provide alternative activities that support children’s development, such as physical exercise, reading, painting, social interaction, and shared play activities, to strengthen parent–child relationships and promote children’s mental well-being and motivation to learn.