The patient in this report was a 73‐year‐old male who was diagnosed with small cell lung cancer (T3N0M0 stage IIB) after presenting with a 5.5 cm tumor detected in the right lower lobe of the lung by radiography. After right lower lobectomy and lymphadenectomy, postoperative adjuvant chemotherapy was administered with cisplatin and etoposide. At 27 months after surgery, the patient complained of wheezing. Tracheal metastasis was identified through computed tomography and bronchoscopy. Biopsy confirmed metastasis of small cell lung cancer. Radiotherapy (60 Gy) was administered to the mediastinal lymph nodes, including the supraclavicular region. The patient then underwent four cycles of carboplatin‐etoposide‐durvalumab, followed by durvalumab maintenance therapy. At 49 months after surgery, the patient complained of discomfort while speaking, leading to the discovery of a nodule in the subglottic space, which confirmed small cell lung cancer metastasis. Radiotherapy (30 Gy) was administered to the larynx and mediastinum, and the patient continued with durvalumab monotherapy. As of 61 months after surgery, he remains recurrence‐free after the second course of radiotherapy. Our favorable outcome could be explained by the synergy between immunotherapy and radiotherapy. Here, we report a rare case of postoperative tracheal metastasis in small cell lung cancer successfully managed with radiotherapy and durvalumab. This shows promise in achieving local disease control and extending survival in postoperative metastatic lesions, highlighting a potential therapeutic approach.