Septic arthritis is a clinical emergency requiring prompt diagnosis and treatment to avoid significant morbidity and mortality. Polyarticular septic arthritis (PASA) accounts for 15% of all infectious arthritides and rarely occurs in immunocompetent adults. Staphylococcus aureus is the most commonly isolated organism, with infection primarily affecting knees, shoulders, elbows, and hips. The morbidity associated with PASA is very high, and mortality in treated cases of PASA may be as high as 50% of cases. We report a case of PASA with associated epidural abscess in a healthy adult male, who presented with complaints of arthralgia and limited range of motion of his left shoulder, wrist, and ankle. He also presented with low back pain and motor weakness associated with an epidural abscess spanning L2-S1, with multilevel vertebral osteomyelitis. Surgical washout of the affected joints as well as decompressive laminectomies was performed, and he received a standard course of intravenous antibiotics. Staphylococcus aureus was isolated from joint aspirations and from blood cultures. The patient had a full neurological and functional recovery postoperatively with no sequelae. To the best of our knowledge this is the only case report of Staphylococcus aureus PASA with concomitant epidural abscess in an immunocompetent adult.