This paper summarizes a three-year quasi-experimental evaluation with school-level assignment of a social-emotional learning (SEL) program for high school students who are at-risk of dropping out before college graduation. The field-initiated program aimed to increase students' social and emotional skills, develop their character, and increase their college-going identities (CGI) with the long-run goal of strengthening students' growth mindset, resilience, and ability to persist to college graduation. There were four interventions that constituted "the treatment": (1) a 10-lesson student-facing CGI curriculum, (2) student-led "critical conversations" with recent alumni about their college experience (3) a research-based CGI coaching rubric for college counselors, and (4) CGI professional development for teachers and counselors. Treatment students were exposed to the curriculum, and both treatment and control students were exposed to business-as-usual college preparation activities, e.g., a curriculum that did not contain specific CGI lessons, but still developed college knowledge and academic readiness. Participating schools were located in suburban Texas (San Antonio, Austin, El Paso, and the Rio Grande Valley). The study sample consisted primarily of low-income and Hispanic students. There were varied levels of implementation fidelity across the treatment schools due to the COVID-19 pandemic. Using a cluster-level quasi-experimental design (QED), treatment effects on students' growth mindset were estimated. The results confirmed the hypothesis that the CGI program led to positive effects on students' growth mindset after two and three years of exposure to the program. This research was funded by an early-phase Education, Innovation, and Research grant from the Department of Education (award number U411C170162).