Massive rotator cuff tears, as classified by size or tendon involvement, are challenging to repair due to scarring, retraction of the tendons, and difficult visualization. Left untreated, these injuries can lead to fatty infiltration and reduced acromiohumeral distance that precludes future repair. The high rate of failure in these patients often impedes an anatomical repair. However, advanced mobilization techniques of the supraspinatus help facilitate a reduction of an otherwise irreparable tear. By performing this repair, more costly procedures may be avoided, such as a superior capsular reconstruction and reverse total shoulder arthroplasty. This Technical Note presents our preferred technique of an all-arthroscopic, medialized repair with double interval slides for the treatment of a massive rotator cuff tear.