Magnetic nanomaterials of different compositions have been examined, focusing on the magnetic field-directed transport of drugs. The size, shape, surface modification and composition variations make every magnetic nanostructure a unique nanocarrier. In this work, we carry out a hydrothermal synthesis of novel manganese-cobalt co-incorporated magnetic ferrite nanoparticles. The particles are characterized using x-ray diffraction, transmission electron microscopy, thermogravimetry and x-ray photoelectron spectroscopy. The size of the nanoparticles is below 10 nm, and they are found to fall under the face-centered cubic system. The nanoparticles are coated with the β-cyclodextrin and folate co-tethered polyethylene glycol. Vibrating sample magnetometry reveals the soft ferromagnetic nature of the nanoparticles with a saturation magnetization value of 28.11 emu g−1 for the coated nanoparticles. The polymer on the nanoparticles allows the loading of the drug feasible, and the encapsulation efficiency is ∼93%. The in vitro release of the drug is monitored and it is observed that the release occurs over 130 h. The cytotoxicity of the free- and camptothecin-loaded manganese-ferrite nanocarrier on breast cancer cell lines is investigated. The IC50 value of the drug-loaded nanocarrier is 2.22 µg mL−1 which is significantly lower than that of the free drug. The drug-encapsulated nanocarrier releases the cargo slowly and continuously and shows increased efficacy, which represents the significance of the nanocarrier. The results present the designed nanomaterial as a suitable anticáncer drug vehicle.