Although popliteal aneurysm is an uncommon condition, it is the most common peripheral artery aneurysm. Peripheral artery aneurysms may dilate or rupture, but can also result in embolism and thrombosis. The optimal management strategy for unoperated popliteal aneurysm and the prophylaxis of thromboembolism in high-risk patients remains to be determined. We present the case of an 81-year-old man with an unoperated popliteal aneurysm with a maximum diameter of 55 mm that was conservatively treated with direct oral anticoagulation and periodic surveillance. The patient also had Alzheimer’s disease and other severe comorbidities. He refused surgery; therefore, we decided to treat him with 30 mg of edoxaban daily to reduce the risk of thrombosis and distal embolism. The patient was followed up with a medical examination and ultrasound monitoring every six months. After a 5-years of follow-up, the size of the aneurysm remained stable, and there were no episodes of thrombosis or limb embolism. No bleeding or adverse effects were reported. These results suggest that a conservative approach with direct oral anticoagulation and periodic surveillance might be an effective strategy for patients at high surgical risk, with limited life expectancy or who refuse operative repair. However, further research and evidence are needed to support direct oral anticoagulation for conservative popliteal aneurysm treatment.