Crystalline polysaccharides are useful for important and rapidly growing applications ranging from advanced energy storage, green electronics, and catalyst or enzyme supports to tissue engineering and biological devices. However, the potential value of chitin in such applications is currently neglected because of its poor swellability, reactivity, and solubility in most commonly used solvents. Here, a high‐efficiency, energy‐saving, and “green” route for the fabrication of extremely strong and transparent chitin films is described in which chitin is dissolved in an aqueous KOH/urea solution and neutralized in aqueous ethanol solution. The neutralization temperature, ethanol concentration, and chitin solution deacetylation time are critical parameters for the self‐assembly of chitin chains and for tuning the morphology and aggregate structures of the resulting chitin hydrogels and films. Moreover, the drawing orientation can produce extremely strong and tough chitin films with a tensile strength, Young's modulus, and work of fracture of 226 MPa, 7.2 GPa, and 20.3 MJ m−3, respectively. The method developed here should contribute to the utilization of seafood waste and, thereby, to the sustainable use of marine resources. Extremely strong and transparent chitin films are prepared using a high‐efficiency, energy‐saving, and “green” route in which chitin is dissolved in an aqueous KOH/urea solution. The chitin films exhibit high strength and high toughness with a tensile strength, Young's modulus, and work of fracture of 226 MPa, 7.2 GPa, and 20.3 MJ m−3, respectively. This method should contribute to the development of sustainable marine resources.