Rapid formation and recurrence of aneurysms accompanied by severe arterial stenosis following radiation therapy (RT) for nasopharyngeal carcinoma (NPC) is an uncommon clinical phenomenon. We present the case of a 51-year-old man who developed subarachnoid hemorrhage years after undergoing RT for NPC. Digital subtraction angiography revealed a ruptured, irregular, wide-neck aneurysm at the posterior communicating segment of the right internal carotid artery (ICA), along with significant stenosis (approximately 80%) at the cervical segment of the same artery. The cervical ICA stenosis was initially treated with stenting, followed by LVIS stent-assisted coil embolization of the aneurysm. Over the next four years, the patient developed three entirely new ICA aneurysms—one of which arose from within the middle portion of the previously placed LVIS stent (a finding not previously reported)—as well as one recurrent aneurysm. This rare case highlights the dynamic nature of RT-induced ICA aneurysm formation and recurrence. Lifelong monitoring and individualized endovascular management are crucial. Considering the fragility of irradiated tissues, extensive arterial involvement, and increased surgical risk from repeat procedures, endovascular treatment was favored over open surgery.