Abstract Background Open pneumothorax with chest wall deficit is a rare chest trauma that is serious and can lead to severe respiratory failure; however, it is a potentially lifesaving injury if utilized appropriately. Case presentation Herein, we report a case of an open pneumothorax with extensive chest wall deficit due to falling from a height and highlight the importance of appropriate evaluation and intervention. The patient was a Japanese man in his 50 s who fell from the 6th floor to the 3rd floor while working at a height. The left chest wall was punctured due to injury, the thoracic cavity was open as if a left anterolateral thoracotomy had been performed, and the left lung had prolapsed from the thoracic cavity to the outside. In our emergency department, tracheal intubation with a double lumen tube for differential positive pressure ventilation and a right thoracic drain were inserted, and an emergency operation was started immediately. A pulmonary suture for lung injury and closure of the left thorax were performed during the surgery. The defect was closed with the remaining tissue, but the anterior thoracic skin with poor blood flow was necrotic, so debridement was undertaken. After his general condition was improved, pedicled latissimus dorsi myocutaneous flap was implanted. He was discharged home on the 63rd hospital day. Conclusions Although open pneumothorax is rare and sometimes presents lurid findings, we highlighted that it is important to quickly assess the life-threatening organ injury, perform positive pressure ventilation by tracheal intubation, thoracic drainage, and wound closure simultaneously respond calmly as a team.