The objective of this case report is to describe the treatment of a dentofacial and temporomandibular joint (TMJ) deformity by means of reconstruction with a customized TMJ prosthesis and orthognathic surgery. The article discusses the therapeutic approach and the importance of functional and esthetic rehabilitation of the patient. A 22-year-old man displayed sequelae of osteomyelitis diagnosed at 6 years of age, including facial asymmetry, laterognathism, unsatisfactory occlusion, and mandibular retrognathism. Computed tomography revealed a deformity of the left mandibular condyle, ramus, and fossa. The patient underwent 1-stage surgery that involved bimaxillary orthognathic surgery and mentoplasty in conjunction with reconstruction of the left TMJ with a customized prosthesis. Postoperatively, substantial improvement was observed in the patient’s facial pattern and masticatory function, and the beneficial changes have been maintained through 2 years of follow-up. The positive outcome in this patient suggests that TMJ reconstruction using a customized prosthesis in combination with computer-guided orthognathic surgery can be a satisfactory approach to correct a mandibular defect. The advantages of 1-stage surgery for the surgeon include shorter treatment time and more predictable results, while the benefits for the patient are good esthetic and functional results and improved quality of life.