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Herpes simplex virus type 1 encephalitis is a neurologic emergency that can present with focal language deficits before the diagnosis becomes clinically apparent. We present an 82-year-old man with diabetes mellitus, hypertension, and hyperlipidemia who developed acute confusion and expressive aphasia after an emergency department visit the previous day for fever, chills, fatigue, sore throat, dizziness, and abdominal discomfort. On arrival for the aphasia presentation, the temperature was 100.3°F, and there were no motor or sensory deficits. Computed tomography of the head, computed tomography angiography of the head and neck, and computed tomography perfusion showed no hemorrhage, large vessel occlusion, or perfusion abnormality. Magnetic resonance imaging of the brain on day 2 showed a focal left temporal lobe abnormality with fluid-attenuated inversion recovery and gradient recalled echo signal change and slight restricted diffusion, without abnormal enhancement. Empiric intravenous acyclovir and broad-spectrum antibiotics were started after magnetic resonance imaging raised concern for encephalitis. Cerebrospinal fluid showed white blood cells 159 cells/µL, 100% lymphocytes, protein 218 mg/dL, glucose 63 mg/dL, and herpes simplex virus type 1 polymerase chain reaction positivity. Electroencephalogram showed diffuse slowing with independent bitemporal sharp waves, at times periodic, without electrographic seizures. His course was complicated by hypotonic hyponatremia, concerning for syndrome of inappropriate antidiuretic hormone secretion, although urine osmolality and urine sodium did not result. Herpes simplex virus type 1 encephalitis should be considered early in older adults with acute aphasia, confusion, recent febrile symptoms, negative vascular imaging, and temporal lobe magnetic resonance imaging abnormalities.