Lithium metal anodes (LMAs) offer substantial promise for high‐energy‐density rechargeable batteries, but managing the complex electrolyte–anode interface is a challenge. Herein, a sustainable dual‐layered interface (SDI) protected Li anode is developed using a joint electrospinning‐rolling technique. In this SDI, polyacrylonitrile (PAN) nanofibers normalize Li‐ion flux across the bulk electrolyte and mitigate electrode volume expansion. More significantly, the continuous release of lithiophilic metal ions aids in constructing alloy interphase in situ, which facilitates Li‐ion transport and uniform lithium deposition. With the dynamic protection of SDI films, cracks in the alloy layer can be promptly repaired during cycling, ensuring efficient control of the electrolyte–anode interface and prolonged stabilization of LMAs. As validation, using a PAN/SnCl₂ film as an SDI prototype, the symmetric cells achieve ultra‐long cycling of 5200 h (≈7 months) at 5 mA cm⁻² and 5 mAh cm⁻². When paired with a sulfur cathode (in ether electrolyte) or a LiNi_0.8Co_0.1Mn_0.1O₂ cathode (in ester electrolyte), the full cells exhibit exceptional stability and rate performance. This sustainable protection strategy for LMAs opens a path to suppress dendrite growth, creating new opportunities for advanced lithium metal batteries.