Objectives: This longitudinal study was designed to examine the growth trajectory of depressive symptoms among early-stage college students and how the development of vigorous, moderate, and light leisure-time physical activity (LTPA) was related to the growth trajectory. Participants: Four hundred and eighty-eight first- and second-year undergraduate students completed measures of depressive symptoms and LTPA at the beginning, middle, and end of a semester. Methods: Latent growth mixture modeling (LGMM) was conducted. Results: On average, students reported mild levels of depressive symptoms with significant variability at the semester start, but the symptoms elevated over time. LGMM identified two trajectories: low/gradual (75.8%) and high/increasing (24.2%). For both groups, neither vigorous nor moderate LTPA development predicted the growth trajectory of depressive symptoms. However, the change of light LTPA was negatively and significantly associated with the growth trajectory. Even when controlling for covariances, increased light LTPA still had a unique effect on buffering depressive symptoms. Conclusion: There is great potential in targeting comprehensive LTPA strategies to improve college students' mental health and promote an active lifestyle.