Chronic posterior glenohumeral joint instability can be a challenging clinical entity for patients and surgeons alike. In the setting of a posterior dislocation, a large anterior humeral impaction injury (reverse Hill-Sachs [HS]) may occur, leading to engagement of the humerus with the posterior glenoid bone, especially during internal rotation of the joint. This is made worse in the setting of ligamentous disruption such as a posterior humeral avulsion of the glenohumeral ligaments (HAGL) lesions. Below is my preferred technique for an anatomic repair of a posterior HAGL lesion in combination with reconstruction of an engaging reverse Hill-Sachs lesion utilizing an unmatched hemitalar allograft.