Purpose: To highlight the efficacy of the Amplatzer septal occluder in endovascular exclusion of an aberrant right subclavian artery aneurysm and reconstruction of the posterior aortic arch wall for subsequent endovascular placement of a thoracic graft. Case Report: A 73-year-old lady with prohibitive surgical risk was found to have a 35 × 39 mm aberrant right subclavian artery aneurysm as well as a 7.6 cm wide thoracic aortic aneurysm. Repair of both defects was performed endoluminally with the patient awake. An Amplatzer septal occluder was used for successful exclusion of the subclavian artery. Additionally, the device enabled reconstruction of the posterior aortic arch wall, thereby providing a landing zone for subsequent placement of a custom-made thoracic endograft. Conclusion: The Amplatzer septal occluder provides an innovative endovascular alternative for complex, large subclavian artery aneurysms.