Purpose: Traditional masculine norms of self-reliance and emotional restraint deter help-seeking, contributing to higher suicide rates in men. Young men online adhering to these norms face elevated risk, worsened by negative digital experiences. Interventions emphasizing masculine-valued physical competency may aid suicide prevention. Methods: A two-arm, four-wave randomized waitlist-controlled trial recruited men aged 17–30 at suicide risk from online forums. Participants received either online social work (OSW) alone or OSW with a three-month competency-based physical training module (CbM) involving high-intensity circuit training. Outcomes were tracked for five months. Results: The CbM group showed significant, lasting gains in self-esteem, physical self-perception, and sport engagement. Suicidal ideation stabilized, with a 95% higher likelihood of improvement versus controls. Perceived physical mastery, not objective fitness, appeared key to mental health benefits. Competency-based physical training module also showed higher engagement. Conclusions: Combining competency-based physical training with OSW provides a scalable, gender-sensitive approach to reducing suicide risk among young men.