Chondroitin sulfate (CS) chains constitute a class of glycosaminoglycans (GAGs). CS chains are distributed on the surfaces of virtually all cells and throughout most extracellular matrices; they are covalently attached to serine residues of core proteoglycan proteins. CS proteoglycans have been implicated as regulators of a variety of biological events, including cell–cell and cell–matrix adhesion, cell proliferation, morphogenesis, and neurite outgrowth. The functional diversity of CS proteoglycans is mainly attributed to the structural variability of the GAG chains, specifically the CS chains. Despite their relatively simple polysaccharide backbones, CS chains acquire remarkable structural variability via several types of enzymatic modifications, including sulfation. Moreover, the sulfation status of CS chains, chain length, number of CS chains per core protein, or combinations thereof can be finely tuned via CS biosynthetic machinery to specify the structure and function of CS proteoglycans. The term “sugar remodeling” refers to the experimental or therapeutic structural alteration of CS chains via perturbation of specific CS biosynthetic enzymes in cells or living organisms; sugar remodeling is a promising approach to the study of CS chain function. This review focuses on our recent findings regarding CS function which have resulted from studies involving sugar remodeling.