Exertional heat stroke is characterized by profound central nervous system dysfunction and core (rectal) temperature typically >40 degrees C. With prompt recognition and response, the probability of survival is excellent; however, there are limited cases with Tc >43.3 degrees C associated with good outcomes. A 23-yr-old male soldier was conducting land navigation training and was found unresponsive by a nonmedical cadre. Emergency medical services personnel obtained a rectal temperature of 44.3 degrees C, which is the highest-ever body core temperature recorded in a patient with exertional heat stroke who survived without significant sequelae. In this case, we report numerous key decisions that contributed to the good outcome. Among those were the use of a GPS-enabled tracking device that enabled the location of the patient on the land navigation course, and the rapid recognition and response by nonmedical personnel at the point of injury. In addition, prioritizing airway, breathing, and circulation over the choice of cooling modality was important in the setting of a patient in acute respiratory distress. Finally, the careful selection of pharmaceutical agents in the Emergency Department minimized additional stress, primarily on the liver and kidneys, which were already significantly stressed. After transfer to a higher level of care due to developing heat-induced disseminated intravascular coagulation and liver failure, the patient was transferred to inpatient rehabilitation 3 wk postinjury. He recovered by 14 mo postinjury, has been medically cleared to return to active duty without limitations, and is continuing his military service. NEW & NOTEWORTHY We present the details surrounding an exertional heat stroke casualty who had the highest-ever body core temperature, 44.3 degrees C, and survived without significant sequelae. Critical decisions that contributed to this outcome, from the point of injury through the first 24 h, are detailed. Treatment considerations included rapid cooling, maintaining the patient's airway, and hemodynamic stability, and minimizing further physiological strain due to the choice of pharmaceutical agents.