Dry reforming of methane (DRM) simultaneously converts the greenhouse gases CH₄ and CO₂ into syngas with an H₂/CO ratio close to 1, offering a promising route for carbon emission reduction and sustainable feedstock production. Ni-based catalysts are attractive due to their low cost and strong CH₄ activation ability, but they suffer from sintering and carbon deposition at high temperatures, resulting in rapid deactivation. This study employed MgO-MgAl₂O₄ composites as supports to synthesize Ni-based catalysts with varying Ce/La molar ratios and doping contents via the sol-gel method. Optimized Ce-La ratios were further modified by Co co-doping to enhance activity and coke resistance. The catalysts were systematically characterized by SEM, BET, XRD, H₂-TPR, CO₂-TPD, TG, and XPS, and their DRM performance was evaluated in a fixed-bed reactor. Ce/La co-doping slightly decreased activity but greatly enhanced coke resistance. The catalyst with a Ce/La ratio of 75:25 and a total doping content of 7% exhibited the lowest coking level (8.19%) after 20 h of DRM, owing to the synergy between Ce-induced oxygen storage/release and La-enhanced CO₂ adsorption. Further incorporation of 3 wt% Co increased CH₄/CO₂ conversions and stabilized the H₂/CO ratio by improving Ni dispersion and reducibility, while also benefiting from Ce-La synergy in tuning oxygen vacancies and surface oxygen migration. This modification raised the fraction of surface reactive oxygen species (Oβ) to 75.9% and suppressed Ni sintering, thereby maintaining high activity and reducing coke formation (9.91%). The results demonstrate that rare-earth co-doping coupled with transition-metal adjustment provides an effective strategy for designing Ni-based DRM catalysts with high activity, stability, and coking resistance, offering valuable guidance for industrial catalyst development.