Abstract Bio‐based alternatives to conventional photothermal hydrophobic materials are urgently required for sustainable ice mitigation. However, integrating robustness, efficient photothermal conversion, and environmental sustainability in one material remains challenging. Here, a bio‐based photothermal hydrophobic elastomer (LPAT) is synthesized via solvent‐free ring‐opening polymerization (ROP) of α‐lipoic acid (LA), with lignin (AL) incorporated as a renewable photothermal filler. Synergistic disulfide and hydrogen bonding endowed LPAT with high toughness (2.79 MJ·m −3 ) and fracture stress (4.45 MPa). Under simulated solar irradiation, LPAT exhibited rapid photothermal conversion, reaching 135 °C with a temperature rise of 112 °C. Hydrophobicity is retained after thermal and stretching cycles, with water contact angles above 116°. LPAT further demonstrated autonomous self‐healing with 80% efficiency and strong underwater adhesion. In deicing tests, it removed 3‐mm ice within 400 s and suppressed accretion under continuous freezing rain. Swelling resistance, reprocessability, and self‐cleaning enhanced its durability across repeated cycles. This work establishes a universal and sustainable platform for integrating high‐performance photothermal and hydrophobic properties, where efficient solar thermal management offers a fossil‐free alternative and facilitates the upcycling of solid waste into advanced energy materials.