The STEM Public Outreach Team (SPOT) at the University of Washington Bothell (UWB) provides training and community building opportunities for diverse STEM students that impact their persistence in STEM majors and careers. The University of Washington Center for Evaluation and Research for STEM Equity (CERSE) evaluated the experiences of SPOT Student Ambassadors to identify and strengthen the program elements that lead to motivation, confidence, and belonging for students from groups underrepresented in STEM fields. Current and former UWB SPOT Student Ambassadors participated in interviews for both formative and summative evaluation over two years identifying motivations, rewards, challenges, and improvements.