We believe that primary care physicians could play a key role in engaging youth with a depression prevention intervention. We developed CATCH-IT (Competent Adulthood Transition with Cognitive Behavioral and Interpersonal Training), which is an adolescent Internet-based behavior change model. We conducted a randomized comparison of two approaches in engaging adolescents with the Internet intervention: primary care physician (PCP) motivational interview + CATCH-IT Internet program (MI) vs PCP brief advice + CATCH-IT Internet program (BA). The participants (N = 84) were recruited by screening for risk of depression in 13 primary care practices. We compared depressive disorder outcomes between groups and within groups over 6 months and examined the potential predictors and moderators of outcomes across both study arms. Depressive symptom scores declined from baseline to 6 weeks with these statistically significant reductions sustained at the 6 months follow-up in both groups. No significant interactions with treatment condition were found. However, by 6 months, the MI group demonstrated significantly fewer depressive episodes and reported less hopelessness as compared with the BA group. Hierarchical linear modeling regressions showed higher ratings of ease of use of the Internet program predicting lower depressive symptom levels over 6 months. In conclusion, a primary care/Internet-based intervention model among adolescents demonstrated reductions in depressed mood over 6 months and may result in fewer depressive episodes.