Previous research on medical students' 'mental health' typically focuses on mental illness with minimal focus on positive mental health indicators, such as well-being and resilience. One malleable predictor of mental health is physical activity (Ravindran et al., 2016); though research on the relationship between different intensities of physical activity and mental health is inconsistent and none have included medical students. The primary purpose of this study was to examine relationships between physical activity, including mild and moderate-to-vigorous physical activity (MVPA), and mental health profiles in a sample of Canadian medical students. A total of N = 125 medical students completed an online survey. Latent profile analysis was performed in Mplus to identify distinct profiles using four continuous latent profile indicators (emotional well-being, social well-being, psychological well-being and resilience). The AUXILIARY function was used to test for differences in physical activity intensities between profiles. Three mental health profiles emerged, showing low (n = 18), moderate (n = 72) and high (n = 36) mental health. The classification quality was good (entropy = 0.81). Individuals in the high mental health profile participated in more mild physical activity (M = 144.28 mins/week; SD = 22.12) and less MVPA (M = 195.86 mins/week; SD = 25.67) compared to students in the moderate and low profiles, though not significantly. This suggests that mild physical activity might be the most effective intensity in supporting mental health among medical students.