Here we report Mn doped cerium oxide films prepared on the LaAlO₃ (0 0 1) substrate via an ethylene glycol modified sol–gel spin coating technique and evaluation of their properties as diluted magnetic semiconductors. Cerium oxide was selected because of its high dielectric constant and fluorite cubic structure, matching the silicon and lanthanum aluminate based electronic devices. The concentration of the Mn ions was varied from 1 to 13 at.% and the influence of this concentration on the structure, surface morphology, optical and magnetic properties of these films was studied using scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy, ellipsometric spectroscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, and magnetic measurements. The incorporation of 7 at.% of Mn ions was found to provide formation of exceptionally smooth films, demonstrating the highest saturation magnetization of 1.75 μ_B/Mn and the coercive field of 487 Gauss. These properties are assigned to the conversion of Ce⁴⁺ to Ce³⁺ upon incorporation of Mn ions into the CeO₂ structure and the oxidation of Mn²⁺ to Mn⁴⁺, creating two oxygen vacancies to preserve the cubic structure of cerium oxide and promoting ferromagnetism.