Few studies have investigated transient global amnesia (TGA) in the context of a concussion and the concussion sequelae following TGA. Here we review the case of a 43-year-old male with onset of transient global anterograde and retrograde amnesia 22 days after a sustained concussion. The patient's head CT, MRI of brain, and EEG were reported normal, and the patient regained full cognitive function 8 h after the TGA episode, with no recollection of the conspiring events. Following the TGA episode, the patient experienced notable worsening of concussive symptoms, including headache, head pressure, anxiety, neck pain, feeling slowed down, fogginess, not feeling right, difficulty remembering, and fatigue. The patient remained symptomatic for 32 days after the TGA episode. We suggest that a lingering window of post-concussion cerebral vulnerability, which may extend beyond clinical recovery, could lead to increased susceptibility to acute cognitive deficits, such as TGA.