To address the growing reliance on natural resources and mitigate the environmental impact of construction waste disposal, waste utilization and eco-friendly production methods are essential. This study presents the development of a green composite using cement paste waste (CPW) and hemicellulose, with mechanical properties further enhanced by replacing 50% of the hemicellulose mass with chitosan. Additionally, the incorporation of natural fibers derived from bamboo and banana was investigated for their impact on the composite’s performance. The composites were fabricated using a hot-pressing technique, and their mechanical properties were evaluated after a three-day curing period. The findings revealed significant influences of heat pressing, fiber reinforcement, and chitosan addition on the mechanical behavior of the composite. Among these factors, the inclusion of chitosan exhibited the most substantial effect, surpassing both fiber reinforcement and heat pressing. Fiber reinforcement demonstrated a greater impact on flexural strength, while heat pressing was more effective in enhancing compressive strength. Notably, the reduction in composite density caused by the partial replacement of hemicellulose with chitosan was compensated through the hot-pressing process. This research is part of foundational studies in the development of high-performance cement composites integrating chitosan and hemicellulose, offering a sustainable alternative to traditional materials in the construction industry.