Monostotic fibrous dysplasia of the mandible is an unusual manifestation of the disease that is usually benign, occurs in young individuals, and is managed by conservative curettage or debridement. We present a case of persistent fibrous dysplasia complicated by pain and intraoral bony exposure that was successfully managed by radical resection and reconstruction with a free fibular flap. Although mandibular fibrous dysplasia is preferentially managed conservatively, treatment of this disease has evolved to a point where total excision and immediate reconstruction may be the treatment of choice and offer the best outcome.