Transparent rigid packaging traditionally relies on fossil fuel-based polymers such as polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP), which contribute to the production of nonbiodegradable waste, landfills, and environmental pollution. Although they exhibit favorable light transmission, their nonbiodegradability raises significant sustainability concerns. In contrast, cellulosic plant fibers are biodegradable. We aim to utilize biomass waste to produce functional, transparent packaging material, thereby lowering the overall carbon footprint. This study explores transparent high-modulus rigid packaging materials using jute fibers. Transparent jute/thiol–ene composites were developed by using ultraviolet (UV) polymerization techniques, achieving light transmission as high as 80% at 550 nm with a 20% fiber content at 1 mm thickness. These composites showed almost a doubling in tensile modulus compared with commercial PET films. Copper nanoparticles were successfully added to provide antimicrobial properties. Hydrolytic degradation analysis confirmed composite biodegradability and its potential as sustainable solutions for packaging applications.