Carbon supported nonprecious metal nanoparticles have gained significant attention for their low cost and excellent properties. However, immobilizing them with good dispersion on carbon supports is still a great challenge. Herein, we report a simple and low cost thermal decomposition method to prepare a high quality carbon supported nickel nanoparticles in presence of casein as carbon source. By optimizing the concentration of carbon source, engineered the particle size from 50 nm to 17 nm and morphology from pyramid to spherical. Further, the impacts of morphology and particle size on the magnetic properties of these nanoparticles are studied. Moreover, thermally stable, biocompatible, low cost with unique magnetic properties makes these materials as potential candidate for various applications including chemisorbers, sensor, and electrochemical uses.