The widespread use of algorithmically curated short videos has led to an unprecedented level of dependence among young people. Similarly, university students are showing increasing short video dependence (SVD), which presents significant societal challenges. Although existing research mostly focuses on behavioral symptoms, the role of core personal traits (CPT) in predisposing individuals to SVD, particularly through cognitive-affective mechanisms, is still insufficiently explained. This study builds on the Interaction of Person-Affect-Cognition-Execution (I-PACE) framework by adding perceived self-relevance (PSR) as an additional mediator and exploring an enhanced serial mediation model using survey data from 825 Chinese undergraduates. The results of the structural equation model show that (1) CPT, fear of missing out (FoMO), and PSR are positively correlated with SVD, whereas perceived self-efficacy (PSE) has a negative correlation with it. (2) FoMO, PSE, and PSR mediate the relationship between CPT and SVD. FoMO also serves as a chain mediator, with the mediation path being CPT → FoMO → PSE → SVD. Since CPT influences SVD both directly and indirectly through the chain mediation of FoMO and PSE, this study enhances the literature on the antecedents of SVD and confirms the impact of cognitive and emotional factors, offering valuable references for research on mechanisms and interventions.