In this work, Ni substituted magnesium spinel ferrites having general formula Mg1−xNixFe2O4 (where x = 0.0, 0.1, 0.15, 0.2, 0.25 and 0.3) were synthesized by standard solid state reaction method. All the samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), DC resistivity measurements. X-ray diffraction analysis confirmed the single spinel phase. The lattice constant decreased with increasing Ni content due to the difference in the ionic radii of Mg2+ and Ni2+ ions. The FT-IR spectra reveled two prominent frequency bands in the wave number range of 400 cm−1 to 600 cm−1, which confirmed the cubic spinel structure of obtained compound and completion of chemical reaction. Magnetic studies revealed that the saturation magnetization increased with the substitution of Ni. The increase in magnetization was explained on the basis of distribution of magnetic and non-magnetic cations among A and B sites of the spinel lattice. A significant influence of cation distribution on DC electrical resistivity and activation energy was observed.