Mulberry silk, derived from Bombyx mori, comprises two key proteins: silk fibroin (SF) and sericin (SS). While SF is widely recognized for its superior mechanical strength and biocompatibility, SS has historically been discarded during processing. However, recent recognition of SS’s bioactive properties, such as antioxidant, antimicrobial, and moisturizing effects, has revived scientific interest in both silk proteins. This chapter presents a comprehensive overview of sustainable extraction methods, structural characterization, and emerging applications of SF and SS. Emphasis is placed on eco-friendly techniques, including enzymatic, microwave-assisted, and ionic liquid-based extractions, which aim to preserve protein integrity and minimize environmental impact. Structural analysis methods, such as FTIR, XRD, and electron microscopy, are highlighted for their role in elucidating the molecular architecture and functional capabilities of silk proteins. SF’s application potential in biomedical fields such as tissue engineering and drug delivery is explored, while SS is examined for use in cosmetics, pharmaceuticals, and food products. Challenges in process standardization, scalability, and functional integration with other biopolymers are also discussed. By reimagining silk as a renewable, multifunctional biomaterial, this study offers valuable insights for advancing sustainable material development, with broad implications for both industry and society.