Arcanbacterium haemolyticum is an uncommon cause of pharyngitis with rash that occurs predominantly among adolescents and that has been only rarely implicated in severe or systemic infections. We report a case of subdural empyema and bacteremia due to A. haemolyticum in an adolescent woman following physical assault with trauma to the head, which required neurosurgical intervention combined with prolonged antibiotic therapy. We additionally describe the previous occurrences of A. haemolyticum culture positivity recorded over a fifteen-year period by the microbiology laboratories of the two large academic medical centers at which this patient received care, and review the epidemiology, laboratory identification, and treatment of this unusual pathogen.