A pectoralis major muscle rupture is a rare injury that mainly occurs during exercise. This study examined the application of rehabilitation, strength and passive range of motion (ROM) change, and subjective assessment for 1 year undertaken after repair surgery of pectoralis major muscle rupture in a Jiu-Jitsu fighter. We hypothesized that the application of ROM exercises and rehabilitation strategies contributed to muscle recovery and successful return to sports. The patient was a 34-year-old man who was injured after falling during a competitive event. The patient had pain and swelling in the front of the chest and shoulder, and the distal chest was deformed. Imaging revealed a complete rupture of the pectoralis major muscle. Reparative surgery was performed by a specialist. Immobilization was performed one week after the surgery. Passive ROM exercises began with the forward flexion 2 weeks after the surgery; abduction and external rotation ROM exercises at 4 weeks; low-intensity muscle strength exercises using tube bands at 6 weeks; machine-based pectoralis major muscle exercises at 3 months. Isokinetic equipment was used to measure horizontal adduction and internal rotation strengths, and the subjective shoulder functional and ROM scores were evaluated. Recovery of shoulder function and ROM occurred at 3 months and muscle recovery at 6 months. The participant was able to return to sports at 5 months and compete at 7 months. Although this study explored only one patient’s post-operative recovery, it suggests that ROM and strength exercises may be effective post-operative strategies for restoring function and strength to enable a return to sports.