Acne vulgaris is one of the most common skin conditions worldwide among adolescents. Beyond its physical manifestations, acne can leave invisible psychological scars. We aimed to examine the protective and risk factors of acne-related quality of life, and its association with mental health outcomes. The analysis included data collected in 2023 from adolescents enrolled in the SEROCoV-KIDS population-based cohort. By combining the Acne Severity and Acne-Quality of Life (Acne-QoL) scales, three groups were established: Acne-LowAQoL (adolescents with acne and low Acne-related Quality of Life), Acne-HighAQoL, and NoAcne-HighAQoL. We used multinomial and logistic regression to assess the association between health behaviours, these groups, and mental health outcomes. Among 335 adolescents (mean age 16.1 years [SD 1.8], 56% female), 65 (19.4%) reported experiencing acne while maintaining a high Acne-QoL, 26 (7.7%) reported having acne and a low Acne-QoL and 244 (72.9%) reported having nearly no acne. Low engagement in physical activity (aOR: 0.30, 95% CI: 0.12-0.77), addictive use of social media (aOR: 3.78, 95%CI: 1.60-8.96), and prolonged screen time (aOR: 2.99, 95%CI: 1.26-7.08) were independently associated with Acne-LowAQoL. Conversely, those from the group Acne-HighAQoL reported higher social support (aOR: 1.95, 95%CI: 1.07-3.54). Adolescents with Acne-LowAQoL showed lower levels of self-esteem, resilience, and increased psychological distress. Among adolescents with acne, physical activity and social support were positively associated with good acne-related quality of life, which translated into better mental health. In contrast, screen time and social media use notably reduced it. Dermatologists should incorporate these considerations into clinical practice to ensure effective patient care.