The occurrence of infection in the ankle and hindfoot presents a formidable surgical challenge. Currently, there is a lack of consensus regarding its treatment strategies. The purpose of this study was to investigate the outcomes of one-stage arthroscopic ankle and tibiotalocalcaneal (TTC) arthrodesis with external fixation in the treatment of septic ankle and hindfoot arthritis. A retrospective consecutive case-series study was conducted involving six patients diagnosed with acute or chronic septic ankle or hindfoot arthritis, who underwent operative intervention entailing thorough debridement, arthroscopically assisted one-stage ankle or TTC fusion, and external fixation. The American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score and visual analog scale (VAS) pain score were determined preoperatively and at the final follow-up. Demographic and clinical data, inclusive of perioperative and postoperative complications, were recorded. Comparisons of AOFAS ankle-hindfoot score and VAS pain score between preoperative measures and those at the final follow-up were conducted using paired t-tests or paired Wilcoxon rank-sum tests. The study cohort comprised two males and four females, with a mean age of 48.7 years (range, 26-75) at the time of surgical intervention. At the final follow-up (mean, 26.5 months; range, 16-48), the AOFAS scores exhibited a significant improvement, ascending from an initial mean of 38.8 (range, 12-57) to 80.0 (range, 54-92) (p = 0.007). VAS scores indicated a substantial reduction in pain, decreasing from 6.5 (range, 4-9) to 0 (range, 0-5) (p = 0.046). All patients had achieved osseous consolidation, with a hindfoot infection control rate of 100%. One-stage arthroscopic ankle and TTC arthrodesis with external fixation is as an effective therapeutic choice for septic ankle or hindfoot arthritis. This approach yields favorable outcomes characterized by effective infection control, favorable osseous consolidation, and significant functional restoration of the affected limb.