BACKGROUND: Schedule-based and in-season factors (e.g., competition type) have been shown to be associated with symptom reporting patterns and injury severity in sport-related concussion (SRC). To determine if acute neurocognitive and symptom presentation following SRC differ by time point within a high school football season. METHODS: Multicenter ambispective cohort of high school football players who sustained a SRC (N = 2594). Timing (early, mid, and late season) of SRC was based on median dates for the start of the pre-season, regular season, and playoffs of each states’ football schedules. Analysis of covariance (ANCOVA) investigated differences across season period groups for: (1) neurocognitive test scores, (2) total symptom scores (TSS), and (3) individual symptom increases from baseline within 1-week post-injury. RESULTS: Significant group differences were observed in TSS, F(2, 2589) = 15.40, p < 0.001, etap(2) = 0.01, and individual symptom increases from baseline, F(2, 2591) = 16.40, p < 0.001, etap(2) = 0.01. Significant increases were seen from baseline to both midseason and late season in both TSS, chi(2) = 24.40, p < 0.001, Phi = 0.10 and individual symptoms, chi(2) = 10.32, p = 0.006, Phi = 0.10. Post hoc tests indicated a linear trend, with late-season injured athletes reporting approximately twice the TSS (13.10 vs. 6.77) and new symptoms (5.70 vs. 2.68) as those with early-season injuries. CONCLUSION: In a cohort of American high school football student-athletes, those suffering SRC in the late-season time period had increased acute symptom burden. SRC sustained later in-season may require more conservative management.