Ewing's sarcoma (ES) is a rare malignant bone tumor that usually affects long bones and the pelvis and is most frequently diagnosed during childhood and adolescence. We report the case of a 30-year-old woman who presented with calcaneus pain and swelling. At the time of diagnosis, imaging tests showed a calcaneal lesion with bone metastases. ES was confirmed by histopathological examination. The patient was treated with palliative chemotherapy and surgery due to the progression of the swelling and local secondary infection. Postoperative computed tomography of the thorax, abdomen, and pelvis revealed lung and bone progression. Second-line chemotherapy was planned, but unfortunately, the patient died of pulmonary embolism. This case illustrates the aggressive nature of calcaneal ES and emphasizes the importance of early recognition and comprehensive evaluation.