Post-traumatic cerebral infarction (PTCI) is a secondary insult which causes global cerebral hypoxia or hypoperfusion after traumatic brain injury, and carries a remarkable high mortality rate. PTCI is usually caused by blunt brain injury with gross hematoma and/or brain herniation. Herein, we present the case of a 91-year-old male who had sustained PTCI following a low-energy penetrating craniocerebral injury due to a nail without evidence of hematoma. The patient survived after a decompressive craniectomy, but permanent neurological damage occurred. This is the first case of profound PTCI following a low-energy penetrating craniocerebral nail injury and reminds clinicians of possibility this rare dreadful complication for care of head-injured patients.