Hemicellulose, a versatile polysaccharide from lignocellulosic biomass, is a key renewable resource for sustainable materials. This chapter reviews advanced processing and simulation-driven design for optimizing its use. It covers environmentally friendly extraction methods like hydrothermal and microwave-assisted techniques, alongside purification processes such as membrane filtration. A central theme is the application of computational tools including molecular dynamics and machine learning to predict material behaviour and accelerate innovation. This integrated approach facilitates the design of high-performance products like hydrogels, bio-based coatings, and films for biomedical and packaging applications. The chapter explores the wide range of uses for hemicellulose, from composites to advanced barrier materials. It concludes by outlining challenges in extraction efficiency, scalability, and integration into the circular bioeconomy, offering a roadmap for replacing synthetic polymers.