Porphyromonas endodontalis is a Gram-negative anaerobic bacterium commonly found in the normal oral flora and is primarily associated with odontogenic infections. Intracranial infections caused by this bacterium are extremely rare. In January 2023, a 10-year-old male was admitted to hospital due to recurrent high fever accompanied by facial swelling for 3 days and one episode of convulsion. Physical examination revealed drowsiness, swelling of the face and neck, and a positive Brudzinski's sign. Laboratory tests showed a white blood cell count of 26.16×10⁹/L, C-reactive protein of 279.57 mg/L, and procalcitonin >100 ng/mL. Cerebrospinal fluid analysis indicated a white blood cell count of 45×10⁹/L and a protein level of 945 mg/L. Head magnetic resonance imaging revealed the formation of bilateral frontal lobe abscesses. Metagenomic next-generation sequencing of blood, cerebrospinal fluid, and pus detected sequences of Porphyromonas endodontalis and various other anaerobic bacteria. A definitive diagnosis of a brain abscess caused by Porphyromonas endodontalis was established. Although initial antimicrobial therapy with vancomycin, meropenem, linezolid, and metronidazole led to transient clinical improvement, the patient experienced recurrent fever, and follow-up imaging showed abscess enlargement with a midline shift. Subsequently, surgical debridement of the subdural and epidural abscesses was performed on the 14th hospital day. Postoperative anti-infective therapy was continued for 6 weeks, resulting in the resolution of fever, absorption of the abscess, and eventual recovery upon discharge.