The design of a single nanosystem with multifunctional surface properties via selecting the appropriate materials and synthesis methods was shown to be crucial for the development of drug delivery systems. In this work, modified magnetic nanocarriers have been successfully constructed using carboxymethylcellulose as the stabilization agents through a facile one-step hydrothermal method. The modified magnetic nanocarriers exhibited a high magnetic saturation of 54.6 emu g⁻¹ and excellent biocompatibility which was detected by a standard MTT cell assay with L929 cell lines; the nanomaterials proved reusable for drug delivery. Subsequently, doxorubicin (DOX) was loaded onto the surface of the nanocarriers and a high loading efficiency of 92.5% was attained. The results from the release characteristics of the DOX-loaded nanocarriers demonstrated that these modified magnetic nanocarriers were highly stable at neutral pH (blood plasma) and strongly pH-responsive for drug delivery in an acidic environment (tumor tissue). The as-prepared multi-functional nanocarriers showed promising potential as drug carriers to improve the therapeutic efficacy of drugs.