Objective: To evaluate the efficacy and credibility of a smartphone-delivered multicomponent lifestyle medicine (LM) intervention, Lifestyle Hub, as a primary modality for managing depressive symptoms in an adult Chinese population. Method: Participants with at least a moderate level of depressive symptoms (n = 79), as indicated by a Patient Health Questionnaire-9 score of ≥10, were randomly assigned to an LM intervention group (LMG; n = 39; eight weekly sessions) or a waitlist control group (WLG; n = 40). Results:The intention-to-treat analysis revealed significant improvements in depressive symptoms (d = 0.66), generalized anxiety symptoms (d = 0.93), insomnia symptoms (d = 0.20), functional impairment (d = 0.22), and health-related quality of life (HRQoL; d = 0.11) from Week 0 (baseline) to Week 9 (immediate postintervention assessment) in the LMG relative to the WLG. Moreover, significantly more health-promoting behaviors (overall health behaviors, health responsibility, physical activity level, nutrition, spiritual growth, and stress management) (d = 0.40-0.89) and higher levels of total activity (d = 0.55) and walking activity (d = 0.55) were found at Week 9 in the LMG relative to the WLG. However, no significant differences were observed in interpersonal relationships, vigorous and moderate exercise levels, sedentary behavior levels, or food frequency questionnaire measures at Week 9 between the LMG and the WLG. From Week 9 to Week 13 (1-month follow-up assessment), a significant within-group reduction in HRQoL (d = 0.50) and an increase in alcohol intake (d = 0.41) were observed in the LMG. Conclusions: The smartphone-delivered multicomponent LM intervention Lifestyle Hub may serve as a primary modality for managing depressive symptoms.What is the public health significance of this article? This is the first study to demonstrate the efficacy and credibility of a smartphone-based multicomponent LM intervention as a primary modality for managing depressive symptoms. The LM approach, which addresses service users' needs and preferences, could be a viable approach to facilitate the management of depressive symptoms.