With high levels of violence and mental distress, street gangs have been classified as a global public health problem requiring immediate attention. However, current interventions suffer from poor theoretical foundations and risk focus. As such, the applicability of an innovative and strengths-based approach to gang intervention (termed Good Lives Model [GLM]) was explored. The GLM assumes offending results when limited prosocial alternatives prevent attainment of 11 universal human needs (e.g., inner peace and community). This study examined the GLM’s etiological assumptions through interviews with 17 gang members; exploring how gangs provide a space to enable attainment of universal needs and factors preventing these being achieved through prosocial means. Findings supported the GLM’s etiological assumptions: participants aimed to achieve all universal needs, with gang membership occurring when prosocial methods were unavailable (e.g., lack of employment opportunities, poor emotion regulation). This supports implementing GLM-consistent interventions to prevent, care, and treat gang-related violence.