People who use substances face disproportionately high rates of HIV and other negative health outcomes. Substance use often intersects with structural and psychosocial barriers that complicate access to and adherence to healthcare, including HIV prevention and treatment. These dynamics highlight the need for interdisciplinary approaches that integrate various perspectives, methods, and areas of expertise to inform both research and mentorship. Interdisciplinarity emphasizes collaboration across disciplines to generate innovative solutions, and it offers a powerful framework for developing interventions as well as mentoring across differences in background, training, and lived experience. Dr. Jae Sevelius, Professor of Medical Psychology in the Department of Psychiatry at Columbia University Medical Center, proposes (1) a plan for their own career development that will expand their research to include substance use and implementation science, (2) a plan to expand their program of research to provide ample interdisciplinary training opportunities for mentees, including developing an interdisciplinary workshop for mentorship training, and (3) a plan to provide mentoring focused on supporting mentees who are launching programs of community-based, patient-oriented research addressing health-related behaviors and outcomes among people who use substances. Dr. Sevelius’ work has been dedicated to developing, implementing, and evaluating health promotion interventions that reduce health risks, including HIV transmission and acquisition, and improve treatment through behavioral changes, community programming, and increased access to culturally appropriate healthcare. Mentee training will leverage the infrastructure and resources of Dr. Sevelius’ ongoing intervention research and their collaborations with multidisciplinary researchers in the areas of HIV, substance use, and health. To expand the scope of their mentoring program, they propose to launch a group-based distance mentoring program, conduct facilitated writing intensives with mentees, and produce scholarship and training in interdisciplinary mentoring. Lastly, Dr. Sevelius proposes to conduct K24-supported research studies that will serve as training vehicles for mentees and advance their research by (1) expanding their research experience and scholarship to include the characterization of substance use within the context of HIV treatment, (2) cultivating expertise in implementation science to identify best practices for the implementation of efficacious HIV prevention interventions among populations who use substances, and (3) gaining experience assessing and contextualizing the effects of substance use on health outcomes in Brazil.