BACKGROUND: Early sport specialization has been associated with an increased risk of musculoskeletal injuries and unfavorable psychological outcomes; however, it is unknown whether sport specialization is associated with worse cognitive, postural, and psychological functions in first-year collegiate student-athletes. METHODS: First-year collegiate multisport (MA) and single-sport (SA) student-athletes were identified using a pre-collegiate sport experience questionnaire. The cognitive, postural, and psychological functions were assessed by the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), Standardized Assessment of Concussion (SAC), Balance Error Scoring System (BESS), and Brief Symptom Inventory 18 (BSI-18). RESULTS: MA student-athletes performed higher in cognitive outcomes (e.g., higher ImPACT visual memory composite scores [ss = 0.056, p < 0.001]), but had higher psychological distress (e.g., higher BSI-18 global severity index [ss = 0.057, p < 0.001]) and no difference in postural stability (p > 0.05) than SA student-athletes. CONCLUSIONS: This study indicated first-year collegiate athletes with a history of sport specialization demonstrate lower cognitive performance but decreased psychological distress and no differences in static postural stability as compared to their MA counterparts. Future studies should consider involving different health measures to better understand the influence of sport specialization on overall physical and mental health.