Cu(0) mediated living radical polymerization was successfully applied to synthesize graft-copolymers from the hemicellulose acetylated galactoglucomannan. Functionalizing the polysaccharide backbone with alpha-bromo isobutyric acid gave rise to a macroinitiator for single-electron-transfer mediated living radical polymerization (SET-LRP). This macroinitiator with a degree of substitution of 0.15 or 0.20 was used in the graft-SET-LRP of methyl methacrylate in dimethyl sulfoxide as well as N-isopropyl acrylamide and acrylamide in water. Kinetic analyses confirm conversions of up to 73% and a con-trolled behavior of the SET-LRP process providing high molecular weight hemicellulose-based hybrid copolymers with a brush-like architecture. Derived graft-copolymers varied significantly in solubility properties, ranging from hydrophobic via temperature responsive water-solubility to water-soluble. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2366-2372, 2011