Background: mTBI is the most common type of head injury among children but diagnosing and managing symptoms are challenging due to heterogeneity. This study used multi-modal analysis to examine how acute mTBI symptoms transition to chronic deficits. Methods: Subjects included a cohort with mild TBI (n=40, 8-18 years old) and age/sex-matched controls (n=27). All participants received symptom assessment, neuropsychological evaluation, ERP assessment, neuroimaging, and serum cytokine analysis. Results were analyzed individually and in multi-modal models to identify important outcome predictors. Results: mTBI resulted in higher symptom burdens compared to controls. There were no group differences in measures of balance, ERP, FA, or MD. Female mTBI participants had lower CNSVS Neurocognition Index scores (p=0.0401) and faster reaction times (p=0.0385) than controls. Repetitive mTBI males had faster psychomotor speed than symptomatic mTBI males (p=0.0260). CTACK levels were higher in female mTBI groups (p= 0.0043), SCGF- levels were lower in male mTBI groups (p=0.0486), and MDC levels were lower in female mTBI groups (p=0.0377) compared to controls. Multi-modal models revealed key predictors from all modalities, despite most measures producing non-statistically significant results in individual analyses. Conclusions: Multi-modal analysis may afford the opportunity to delineate complex mTBI pathology and provide better identification of biomarkers than unimodal analysis.