Recent evidence suggests significant short-term neurocognitive deficits following mild traumatic brain injury (MTBI) in sports. However, sequelae of mild head injuries is complicated by many factors including a history of multiple head injuries and injury severity. Few studies have considered the influence these variables may have on proper classification of a MTBI and their meaning for return-to-play guidelines. This study presents the short-term neuropsychological and balance outcomes of four college athletes who sustained mild head injuries of different severity (grade I, grade II, grade III and multiple head injured with a grade II based on American Academy of Neurology guidelines). The results demonstrated that self-report symptoms of concussion were slow to resolve in the grade III and multiple concussed individuals. For neuropsychological testing, Trails A & B, Symbol Digit Modalities Test and Digits Span Backwards were the most sensitive in identifying differences between the injuries. For balance assessments using the Neurocom Smart Balance System, the Sensory Organization Test and Reaction Time were also important variables in detecting differences among the various injuries. When these data are used together, it can assist physicians in determining safe return-to-play for athletes who sustain MTBI. There are contradindications in the numerous grading systems and return-to-play guidelines for MTBI. The results from this study provides new evidence which can be assimilated into a valid grading scale for MTBI sustained in sport.