ABSTRACT Developing zinc‐air batteries (ZABs) for high‐current‐density operation is critical for high‐power applications, yet remains limited by the lack of electrocatalysts that integrate high activity, durability, and low cost. Cu single‐atom catalysts offer a promising alternative to platinum group metals, but their performance is often hindered by inappropriate adsorption of oxygenated intermediates and the instability of Cu active sites. Here, we report a topological defect‐engineered Cu single‐atom catalyst on nitrogen‐doped carbon nanofibers (Cu/TD 1/5 –NCFs), where topological‐defect‐induced geometric confinement stabilizes Cu–N x sites and suppresses Cu migration, aggregation, leaching, and deactivation during operation. Meanwhile, the topological‐defect‐regulated electronic environment optimizes the adsorption of oxygenated intermediates, thereby facilitating ORR kinetics. As a result, the assembled ZAB delivers ultralong cycling stability exceeding 2000 h at 100 mA cm −2 , outperforming most reported systems under similar conditions. The robustness of this strategy is further supported by consistent reproducibility and general applicability across different metal precursors and catalyst configurations. Collectively, these findings highlight topological‐defect‐induced geometric confinement as an effective strategy for stabilizing single‐atom catalysts and enabling durable energy devices.