Background: There is an increasing concern over adolescent concussions in sports due to risks of long-term negative effects. This study analyzed data over three school years on reported concussion incidence rates by season, high school grade levels and gender, and reported symptoms by school nurses versus athletic trainers, from New Jersey student-athlete concussion data available from an online school-based surveillance system. Methods: School nurses and athletic trainers reported 300 concussions within five days from when each occurred over three school years, 2015-2018, in team sports and physical education in New Jersey high schools. Analysis was further conducted on symptoms and number of symptoms reported by school nurses versus school athletic trainers for each documented student-athlete concussion. Estimated concussion incidence rates were calculated using state agency verified school enrollment data. Findings: Concussions most commonly occurred during fall, followed by spring, then winter. Concussion incidence rates ranged from 6.3/1000 (4.99, 7.55) -9.1/1000 (7.27, 10.98) students over the three school years of the study. Athletic trainers completed 86% of the reports while nurses completed 11% (position or title of 3%, or n = 7, were not disclosed); the values were similar when considering only fall pre-season and regular season sports (88, 10, 2%, respectively). On average, across the three school years, athletic trainers reported about 3.5 symptoms per report while nurses reported 2.7 (values in fall seasons only were 3.7 and 3.1, respectively.) Conclusions: Certified athletic trainers, compared to school nurses, more often completed concussion report forms and reported more symptoms per injured student, perhaps due partly to closer contact and immediate care provided after injury. Additionally, this study had a higher concussion incidence rate during fall sports seasons compared to winter and spring. Future research can further improve our understanding of concussions among adolescent student-athletes to better inform concussion identification, management and recovery protocols.