Mental health and substance use fields suffer from underrepresentation of racially and ethnically minoritized, first-generation college student, and female members. The homogeny of the current workforce can impede scientific productivity, creativity, and problem-solving in addressing health-related issues. Our team developed the Teen Science Ambassador Program (TSAP) to provide underrepresented minoritized (URM) high school students with science-focused education, research opportunities, and mentoring within their community. The goals of the current study were to describe the logic model and structure of TSAP, provide access to a resource bank to facilitate replication across communities, and present preliminary mixed-methods outcome data to guide development of the program. Qualitative and quantitative results from our first two cohorts (N = 18; 89% girls; 72% Black or African American; 22% Hispanic or Latino; 40% of parents did not have a college degree) indicated TSAP contributed to sustained interest, increased confidence, and enhanced sense of belonging in science-related fields, especially those pertaining to mental health and substance use. These findings highlight the program's promise to facilitate entry and sustainment of URM and female youth within the biomedical sciences. Given the urgent need to promote diversity in the mental health and biomedical workforce, we provide readers with a resource bank to facilitate replication across communities.