Small-cell carcinoma occasionally occurs in the gastrointestinal tract, with rare reports of it in the biliary system. When it does occur in the biliary system, it is mainly within the gallbladder, and those arising in the extrahepatic bile duct are extremely rare with only seven reported cases to date. A 62-year-old man with this unusual condition is documented. The patient was preoperatively diagnosed as having small-cell carcinoma on the basis of a biopsy specimen and was treated with multidisciplinary management, which consisted of preoperative chemotherapy, a curative resection, adjuvant chemotherapy, and radiation therapy. The patient died 23 months after the initial diagnosis (20 months after surgery). To the best of our knowledge, the survival time of this case was the longest among reported cases, and multidisciplinary management might contribute to a prolonged survival.