Lemierre's syndrome is a rare disease associated with significant morbidity and mortality. It begins with an oropharyngeal infection, which spreads locally to involve the internal jugular vein causing thrombophlebitis, followed by distant spread and metastatic infections. Affected individuals are commonly young adults. Causative organisms are usually oropharyngeal flora, most commonly being the anaerobe Fusobacterium necrophorum. Porphyromonas asaccharolytica is a rare etiological agent with only three cases being reported in the literature. This case report describes a previously healthy 22-year-old man who initially presented with acute tonsillitis and was later found to have left internal jugular vein thrombophlebitis along with bilateral septic emboli to the lungs. The patient was treated with a five-week course of ampicillin-sulbactam and metronidazole. Subsequent imaging also showed progression of internal jugular vein thrombus, for which warfarin was given for three months for anticoagulation.