The dispersion stabilization of colloidal particles and subsequent construction of functional materials are of great interest in areas ranging from colloid chemistry to materials science. A promising strategy is the spatial immobilization of colloidal particles within gel scaffolds. However, conventional gels readily deform and even collapse when changes in environmental conditions occur. Herein, we describe the enzyme-catalyzed bottom-up synthesis of mechanically and physicochemically stable nanoribbon network hydrogels composed of crystalline cellulose oligomers in which cellulose nanocrystals (CNCs) as model colloidal particles are immobilized spatially. The stiffness of the hydrogels increased with the amount of CNCs incorporated. Filling the void space of the hydrogels with hydrophobic polymers resulted in polymer nanocomposites with excellent mechanical properties. The nanoribbon networks will be useful for demonstrating the potential functions of colloidal particles.