Synthetic methods for modifying the carboxylic acid groups of hyperbranched thin film grafts were studied. Amidation, esterification, reduction, and alkylation reactions of carboxylic acid derivatives that proceed in high conversion (>90%) are described. The stability of ultrathin, hyperbranched film grafts attached to self-assembled monolayers on gold to conditions of strong base, strong acid, heat, and organic solvents is detailed. Practical procedures that can be used to prepare and modify poly(acrylic acid) hyperbranched grafts on gold, polyethylene film, and powder for use in the synthesis of cationic polyelectrolyte grafts, for use in the synthesis of poly(allyl alcohol) grafts, for use in the synthesis of poly(allyl ester) grafts, and for use as substrates for organometallic chemistry and further graft chemistry are discussed.