The field of heritage language (HL) education has offered practical guidelines for developing and maintaining Spanish as a HL for Hispanic students. However, in regions with limited racial and ethnic diversity, beyond the language development goals, the HL classrooms can also serve as a vital space for promoting students' academic, social, and psychological well-being in higher education. This paper examines a service-learning (SL) project at a predominantly White institution in the Midwest, aimed at building relationships and advocating for supportive access to higher education among U.S. Latinx students. College students enrolled in an HL Spanish course partnered with high school students in an HL class to foster mentoring relationships, organize a campus visit, and produce creative written revista based on personal testimonies. The paper explores the educational experiences of college students, their perceptions of support needs, and the impact of SL, using data (N = 25) collected from reflection writings, questionnaires, and interviews conducted over two semesters. Ultimately, it advocates for greater collaboration between high school and college HL programs to promote access to high-impact practices like SL, which can contribute to both educational attainment and the maintenance of HL among U.S. Latinx students.