A combination of an anterior sternoclavicular (SC) joint dislocation with a midshaft clavicle fracture is an extremely rare injury. If left untreated, it can lead to severely impaired function of the shoulder with a high risk for complications. A 45-year-old male patient presented with pain and impaired range of motion (ROM) in the left shoulder after a mountain bike crash. Radiographs and a computed tomography scan showed an anterior dislocation of the left SC joint and an ipsilateral midshaft fracture of the clavicle. Open reduction and internal fixation (ORIF) of the clavicle combined with SC joint stabilization using transosseous sutures was performed. Postoperatively, a shoulder-arm bandage was applied with passive motion starting on the first postoperative day. During follow-up, the patient showed an improved clinical function and could return to work after three weeks. Radiographs at eight weeks showed fracture healing without any signs of recurrent SC dislocation. At the final follow-up at 12 weeks, the patient returned to his pre-injury activity level and recreational sports. Despite minimal redislocation in the SC joint, the Constant-Murley Score showed a continuous improvement with 93%, compared to the contralateral side. In conclusion, surgical treatment of anterior SC joint dislocation with a midshaft clavicle fracture can restore shoulder function with no surgery-associated complications.