Popliteal artery entrapment syndrome (PAES) is a rare vascular disorder characterized by the compression of the popliteal artery behind the knee, primarily affecting physically active individuals. This is a case of a 36-year-old man who presented with a 1-week history of sudden-onset left leg pain. Diagnostic evaluation, including physical examination, color duplex ultrasonography, computed tomography, and magnetic resonance imaging, revealed a popliteal artery pseudoaneurysm caused by type 5 PAES. The patient underwent surgical exploration to release the entrapment, followed by an interposition graft with the ipsilateral great saphenous vein. Patient postoperative recovery was uneventful, with significant symptomatic improvement. This case underscores the significance of considering PAES as a differential diagnosis in young patients with popliteal artery aneurysms and highlights the necessity for prompt diagnosis and treatment to prevent limb-threatening complications.