In this paper, the 10 wt% Ni/Al₂O₃-MgO (10Ni/MA), 5 wt% Ni-5 wt% Ce/Al₂O₃-MgO (5Ni5Ce/MA), and 5 wt% Ni-5 wt% Co/Al₂O₃-MgO (5Ni5Co/MA) catalysts were prepared by an impregnation method. The effects of CeO₂ and Co doping on the physicochemical properties of the Ni/Al₂O₃-MgO catalyst were comprehensively studied by N₂ adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), H₂ temperature programmed reduction (H₂-TPR), CO₂ temperature programmed reduction (CO₂-TPD), and thermogravimetric analysis (TGA). The effects on catalytic performance for the combined steam and CO₂ reforming of methane with the low steam-to-carbon ratio (S/C ratio) were evaluated at 620 °C under atmospheric pressure. The appearance of CeO₂ and Co enhanced the oxygen species at the surface that decreased the coke deposits from 17% for the Ni/MA catalyst to 11–12% for the 5Ni5Ce/MA and 5Ni5Co/MA catalysts. The oxygen vacancies in the 5Ni5Ce/MA catalyst promoted water activation and dissociation, producing surface oxygen with a relatively high H₂/CO ratio (1.6). With the relatively low H₂/CO ratio (1.3), the oxygen species at the surface was enhanced by CO₂ activation-dissociation via the redox potential in the 5Ni5Co/MA catalyst. The improvement of H₂O and CO₂ dissociative adsorption allowed the 5Ni5Ce/MA and 5Ni5Co/MA catalysts to resist the carbon formation, requiring only a low amount of steam to be added.