Exertional heatstroke (EHS) is a life-threatening condition to all who engage in vigorous physical exertion. It will result in fatal multi-organ failure. The prognosis of heatstroke is directly related to the degree of hyperthermia and the duration. Thus, early diagnosis and rapid cooling are crucial for the patient’s survival. We present a 19-year-old man who had sudden onset of hyperthermia, seizure and renal function impairment after excessive exercise, and exertional heatstroke was diagnosed in the emergency department. After prompt diagnosis and treatment, the patient was discharged with stable condition. Relevant literature was also reviewed and discussed.