Synthetic, functionalized, graft copolymers of polyesters and amino acids are provided. The copolymers are formed in one embodiment by providing a linear polyester-poly(amino acid) copolymer, and reacting the amino acid groups in the linear polymer with an amino acid derivative in a polymerization reaction to form a comb-like, graft copolymer including a polyester-amino acid backbone and polyamino acid side chains extending from the amino acid groups in the backbone. The poly(amino acid) includes functional groups which permit the covalent or ionic attachment of a biological molecule to the graft copolymer. The functionalized graft copolymers can be used in a wide range of biomedical applications including tissue engineering and drug delivery.