Disclosed is an improved method of making hydrophobic and hydrophilic graft polymers, which method comprises the steps of (a) reacting copolymerizable monomers to form an organic polymeric backbone having a weight average molecular weight of from about 15,000 grams/mole to about 200,000 grams/mole and a plurality of organic halide moieties covalently bonded to the polymeric backbone and pendant from the polymeric backbone and then, without a separate purification or isolation step; (b) reacting copolymerizable monomers with the organic halide moieties of the polymeric backbone by atom transfer free radical polymerization in the presence of a catalytic amount of a Cu(I) salt or other transition metal species complexed to a ligand suitable for solubilizing the salt in the reaction mixture to form a plurality of polymeric side chains covalently bonded to the polymeric backbone and pendant from the polymeric backbone and having a weight average molecular weight of from about 500 grams/mole to about 200,000 grams/mole, wherein the polymeric back bone and the plurality of polymeric side chains form hydrophilic and hydrophobic graft polymers having a weight average molecular weight of from about 16,000 grams/mole to about 10,000,000 grams/mole.