In recent years, the pressing global challenges of environmental sustainability, resource scarcity, and waste management have led to increased interest in converting waste biomass into high-value products aligned with the principles of a circular bioeconomy. Such an approach utilizes renewable resources, reduces dependence on fossil fuels, and mitigates greenhouse gas emissions, thereby offering viable pathways to address environmental concerns and focusing on economic development. This chapter explains the possibilities, challenges, and real-world considerations involved in transforming waste biomass into valuable bioproducts. This chapter first examines the abundance and diversity of waste biomass sources, highlighting their global distribution and potential for valorization. It then explores how chemistry, biology, engineering, and data analytics converge to develop both conventional and emerging conversion technologies. Further, the focus is on ensuring product quality standards and keeping pace with changing market needs, highlighting economic feasibility, scale-up hurdles, and environmental performance measures. Case studies illustrate real-world applications and insights, while discussions on policy frameworks and prospects offer strategic guidance for stakeholders. By providing an overview of these interconnected elements, the chapter seeks to empower researchers, industry professionals, and policymakers to make decisions that advance waste biomass conversion toward large-scale, sustainable implementation.