Background <p>This study investigates the relationship between psychological capital and subjective academic achievement among middle school students. It further explores the chain mediating role of adolescent internalizing problems and life attitude in this relationship.</p> Methods <p>A cross-sectional survey, conducted in 2024, examined the relationships among psychological capital, adolescent internalizing problems, life attitude, and subjective academic achievement in a convenience sample of 1,019 middle school students from Chengdu, China. Data were analyzed using descriptive statistics, correlation analyses, and a chain mediation model.</p> Results <p>Psychological capital significantly predicted subjective academic achievement, in which adolescent internalizing problems and life attitude served as mediators. Specifically, higher psychological capital was associated with fewer adolescent internalizing problems, more positive life attitude, and, ultimately, improved subjective academic achievement.</p> Conclusion <p>These findings offer novel theoretical insights, emphasizing the pivotal role of psychological capital and positive life attitude in educational interventions aimed at fostering student academic achievement.</p>