The design and development of water dispersible, pH responsive peptide mimic shell cross-linked magnetic nanocarriers (PMNCs) using a facile soft-chemical approach is reported. These nanocarriers have an average size about 10 nm, are resistant to protein adsorption in physiological medium, and transform from a negatively charged to a positively charged form in the acidic environment. The terminal amino acid on the shell of the magnetic nanocarriers allows us to create functionalized exteriors with high densities of organic moieties (both amine and carboxyl) for conjugation of drug molecules. The drug-loading efficiency of the nanocarriers is investigated using doxorubicin hydrochloride (DOX) as a model drug to evaluate their potential as a carrier system. Results show high loading affinity of nanocarriers for anticancer drug, their sustained release profile, magnetic-field-induced heating, and substantial cellular internalization. Moreover, the enhanced toxicity to tumor cells by DOX-loaded PMNCs (DOX-PMNCs) under an AC magntic field suggest their potential for combination therapy involving hyperthermia and chemotherapy.