Reverse total shoulder arthroplasty (RTSA) is a well established treatment that provides reproducible results in the treatment of shoulder arthritis and rotator cuff deficiency in the older patient population. However, the results of arthroplasty in younger, more active patients are currently unclear and not as predictable. The purpose of this study is to evaluate the mid-term results of RTSA for patients aged younger than 60 years. A retrospective review of twenty-six patients (twenty six RTSAs) with a mean age of 58.3 years was performed. Minimum follow-up of 5 years was available at a mean follow-up of 73.3 months postoperatively (range, 60–84 months). The preoperative conditions compelling RTSA were as follows: failed rotator cuff repair (17), fracture sequelae (5), failed arthroplasty (1), and cuff tear arthropathy (CTA) (3). We assessed range-of-motion and strength, visual analog scale, American Shoulder and Elbow Surgeons (ASES), and Constant scores. Radiographs were also evaluated for component loosening and scapular notching. All patients were analyzed radiologically and clinically using patient-reported outcome measures. Active forward elevation improved from 56° to 134° and average active external rotation improved from 10.0° to 19.6°. Scores measured with a visual analog pain scale, the Constant score, and the American Shoulder and Elbow Surgeons (ASES) scale all improved significantly. The Visual analog scale (VAS) score for pain improved from 7.5 to 3.0 and the ASES score improved from 31.4 to 72.4, respectively. The normalized postoperative mean Constant score was 88.03. No radiograph showed loosening of the implant at follow-up. Complications included one traumatic subscapularis rupture at six weeks, and one case of periprosthetic fracture. The remaining twenty-four patients were satisfied with the outcome at the time of the latest follow-up and had returned to their desired activity. RTSA in younger patients provided significant subjective improvement in self-assessed shoulder comfort and substantial gain in overall function. Implant loosening and glenoid wear did not appear to be concerns in the mid-term despite the high activity levels of younger patients. Longer-term studies are required to determine whether similar results are maintained over time.