Background <p><i>Staphylococcus aureus</i> is a major pathogen responsible for both community-acquired and hospital-acquired infections. However, disseminated infections complicated by pulmonary abscesses and osteomyelitis are rare in otherwise healthy children.</p> Case presentation <p>We report a case of a previously healthy 12-year-old boy who presented with a 7-day history of cough and a 5-day history of fever and progressive swelling of the left upper limb after self-manipulating a right forearm furuncle. Physical examination and imaging revealed multifocal pulmonary abscesses and osteomyelitis of the left humerus. Blood cultures confirmed the presence of methicillin-resistant <i>Staphylococcus aureus</i> (MRSA). Despite initial empirical antibiotic therapy, the patient’s symptoms persisted, necessitating four surgical interventions. The first two surgeries involved debridement with antibiotic-loaded calcium sulfate implantation. Nineteen months later, due to nonunion of the proximal humerus, the patient underwent open reduction and internal fixation with autologous iliac bone grafting, followed by subsequent removal of the internal fixation two years later. This staged approach, starting with infection control followed by delayed reconstruction, led to successful bone union, with complete resolution of the pulmonary abscesses on follow-up imaging.</p> Conclusion <p>This case highlights the potential for rapid hematogenous dissemination of <i>Staphylococcus aureus</i> leading to complex multi-organ involvement even in healthy pediatric patients. Prompt diagnosis, multidisciplinary management, and combined surgical and antibiotic therapy are critical for favorable outcomes.</p> Clinical trial number <p>Not applicable.</p>