Youth substance use (SU) has been linked to adverse mental health outcomes. For those youth involved in public sector systems of care, reports of SU are consistently high compared to general populations. These public sector services systems of care include mental health, juvenile justice, child welfare, homeless intervention services, as well as SU service systems. In addition, minority and marginalized youth tend to report disproportionately high SU. As an example, in Hawaiʻi, youth who are Native Hawaiian (NH), Micronesian, or who identify as sexual or gender minorities not only report elevated rates of SU, but are overrepresented in public sectors. In order to reduce youth SU health disparities, access to and quality of the system of care for youth must improve. To inform systems change, this needs assessment study used qualitative methods to engage professionals in Hawaiʻi working within public sectors that may intersect with youth SU service system of care. Professionals identified several themes which have implications for practice, policy, and research: colonialism and inclusivity at the macro level, the need for policies at the exo level, meso level changes regarding family and community, and stigma and discrimination at the micro level.