<p>The outcome of patients with severe traumatic brain injury presenting with dilated pupils is generally poor, and decompression surgery at the earliest possible is warranted in such cases. Our strategy for managing patients with severe traumatic brain injury comprises completing the series of treatment provided at prehospital, trauma bay, intensive care unit, and rehabilitation center at a single department in a hospital (All–in–One Strategy). Herein, we report the case of a patient with severe traumatic brain injury who was successfully treated using this strategy and who survived to hospital discharge with a good neurological outcome. A 19–year–old male was injured in a traffic accident at midnight, following which a physician–staffed ambulance was dispatched from our hospital. When the physician contacted the patient at the emergency site, the patient was comatose and had developed Cushing reflex. The physician notified the trauma bay for emergency surgery at the emergency site.</p><p>Soon after arriving at the trauma bay, the patient underwent head computed tomography, revealing bilateral acute subdural hematoma with multiple contusions. An emergency trepana­tion was performed 58 min after the patient’s arrival at the hospital because his pupils were dilated. Subsequently, the patient was transferred to the operation room and decompressive craniotomy performed 74 min after his arrival. The patient recovered to eat and walk on his own and survived to discharge at day 84 with a Glasgow Outcome Scale category of moderate disability.</p>