Autoimmune glial fibrillar acidic protein (GFAP) astrocytopathy is a rare autoimmune neuroinflammatory disorder that affects the central nervous system. We present a case of GFAP astrocytopathy in a middle-aged male who presented with constitutional symptoms, encephalopathy and lower extremity weakness and numbness. Initially MRI of the spine was normal, but he subsequently developed longitudinally extensive myelitis and meningoencephalitis. Workup for infectious aetiologies was negative and the patient's clinical course worsened despite broad antimicrobial coverage. Ultimately, he was found to have anti-GFAP antibodies in his cerebral spinal fluid consistent with GFAP astrocytopathy. He was treated with steroids and plasmapheresis with clinical and radiographic improvement. This case demonstrates the temporal evolution of myelitis on MRI in a case of steroid-refractory GFAP astrocytopathy.