Background <p>Social media has become an integral part of college students’ daily lives, yet the issues of information overload and emotional distress it brings are increasingly prominent. Previous studies have primarily focused on the associations between social media use and psychological outcomes such as well-being, anxiety, or depression, while paying insufficient attention to the underlying mechanisms through which it influences individuals’ core self-evaluation. This study aims to explore the mediating roles of information overload and fear of missing out (FoMO) in the relationship between social media use and core self-evaluation.</p> Method <p>A cross-sectional survey was conducted in a prefecture-level city in Henan Province, China, from November to December 2023, involving two universities. The questionnaire was administered online via the Wenjuanxing platform. A total of 1519 college students participated in the cross-sectional survey.</p> Results <p>Results from the chained mediation model indicate that social media use does not directly and positively predict college students’ core self-evaluation; rather, its influence is primarily exerted indirectly through information overload and fear of missing out. Both variables serve as significant mediators and form a sequential mediating pathway.</p> Conclusion <p>Information overload and FoMO were identified as partial mediators in the correlation between social media usage and core self-evaluation among college students, highlighting the existence of a chain mediation mechanism linking them. This study elucidates the mechanism through which social media influences college students’ self-cognition. Theoretically, it advances the understanding of the relationship between social media use and core self-evaluation; practically, it offers insights for universities to develop interventions targeting information management and emotion regulation, thereby supporting students’ mental health.</p>