The article reviews the properties and applications of protein-based fibers, which combine unique mechanical properties with biocompatibility and biodegradability. The authors highlight the growing need for sustainable materials, leading to a revival in the study of protein fibers such as keratin, collagen, elastin, and silk. These fibers can mimic natural functions that are difficult to achieve with synthetic polymer-based fibers. The review covers the synthesis methods, hierarchical structures, and applications of these fibers, including air and water filtration, energy conversion, smart textiles, and biomedical uses. Key topics include the assembly processes of natural protein fibers, the development of man-made protein fibers through recombinant techniques, and the post-processing methods to enhance their mechanical properties. The article also discusses the use of protein fibers in mimicking the extracellular matrix (ECM) for tissue engineering and their applications in textiles.The article reviews the properties and applications of protein-based fibers, which combine unique mechanical properties with biocompatibility and biodegradability. The authors highlight the growing need for sustainable materials, leading to a revival in the study of protein fibers such as keratin, collagen, elastin, and silk. These fibers can mimic natural functions that are difficult to achieve with synthetic polymer-based fibers. The review covers the synthesis methods, hierarchical structures, and applications of these fibers, including air and water filtration, energy conversion, smart textiles, and biomedical uses. Key topics include the assembly processes of natural protein fibers, the development of man-made protein fibers through recombinant techniques, and the post-processing methods to enhance their mechanical properties. The article also discusses the use of protein fibers in mimicking the extracellular matrix (ECM) for tissue engineering and their applications in textiles.