<p>Establishing a robust circular bioeconomy relies on the efficient valorization of non-traditional feedstocks, C1 compounds (CO₂, methanol, formate), plastic waste, and biomass-derived chemicals. Glycolaldehyde, the simplest α-hydroxyaldehyde and a diose sugar, is central to these efforts as a uniquely versatile metabolic hub. Inspired by its critical role in prebiotic chemistry, this review evaluates the metabolic landscape of glycolaldehyde-centric metabolic pathways and their capacity to bridge diverse feedstocks with central metabolism. We first survey routes for producing glycolaldehyde from C1 feedstocks, lignocellulose, and plastic waste. We then examine natural pathways that assimilate glycolaldehyde into biomass and new-to-nature pathways for carbon elongation from glycolaldehyde. Finally, we outline perspectives on consolidated bioprocessing and hybrid electrochemical–biological systems, positioning glycolaldehyde as a critical metabolic bridge toward sustainable biomanufacturing.</p>