Background: Current joint-sparing treatment options for massive, irreparable rotator cuff tears aim to prevent superior migration of the humeral head and maintain the subacromial space. Although options such as superior capsular reconstruction and posterosuperior tendon transfer may appropriately restore function and reduce pain, these procedures harbor significant comorbidity and intense postoperative rehabilitation. Recently, studies have demonstrated excellent results from a subacromial balloon spacer composed of a biocompatible copolymer that degrades over the 12 months following implantation. This spacer enables a more anatomic position of the humeral head to restore normal shoulder biomechanics. Indications: The subacromial balloon spacer is primarily indicated in patients with massive, irreparable rotator cuff tears who demonstrate proximal humeral migration. Contraindications include subscapularis or teres minor tendon tears, deltoid dysfunction, and pseudoparalysis. Technique Description: Standard arthroscopic portals are established, and a diagnostic arthroscopy is performed to assess the glenohumeral joint space and subscapularis tendon. A subacromial bursectomy is performed without proceeding medial to the superior glenoid rim. The subacromial space is measured utilizing an arthroscopic measurement probe to ensure that the selected spacer will lie slightly medial to the glenoid. The rotator cuff is then reapproximated from the lateral to medial aspect of the tear and repaired via a side-to-side manner with high strength, nonabsorbable tape, and a self-capturing suture device. Following repair, the deployment device is inserted through the lateral portal, placed slightly medial to the glenoid, and inflated with saline. Results: Utilization of the described subacromial balloon augmentation provides significant pain relief by restoring glenohumeral biomechanics, improvements in range of motion, and an enhancement in quality of life. Discussion: This case report and video review of a technique for utilizing a subacromial balloon spacer demonstrates an effective, simple, and safe treatment for massive, irreparable rotator cuff tears. Positive results rely on appropriate inflation and secure fixation. Recent clinical trial data suggest that functional outcomes for the subacromial balloon spacer are noninferior to that of partial rotator cuff repair. These promising results suggest that the subacromial balloon spacer may prove an essential tool for joint-preserving surgery following massive, irreparable rotator cuff tears.