In recent years, student engagement in high-impact educational practices (HIPs) has received significant attention from academics. However, a lack of focus persists regarding the factors responsible for its engagement. Our study utilizes the presage-process-product (3P) model of student learning and engagement to investigate the dynamics between personal and institutional elements, scrutinizing their impact on student interpersonal interaction and its subsequent engagement in HIPs. By applying a moderated mediation empirical model to a group of 2,940 Chinese undergraduates, our findings highlight the significant role of students' social and emotional skills (SES) in enhancing their engagement in HIPs, mediated by interpersonal interaction. Additionally, school support emerges as a crucial moderating factor, strengthening the effects of SES on interpersonal interaction and the indirect effect of SES on student engagement in HIPs via interpersonal interaction. Our study contributes significantly to theory by confirming students' personal characteristics (their SES) as facilitators driving their participation in HIPs. It also identifies the mechanisms and boundary conditions of this influential process, offering insights for enhancing HIP participation at both individual and institutional levels.