Glucose-free and glucose-containing LaCoO₃(-G), La_0.9Sr_0.1CoO₃(-G), and La_0.9Ce_0.1CoO₃(-G) perovskite catalysts were synthesized via the sol–gel method, over which the oxidation performance of high-concentration CO was investigated. The experimental results indicate that the catalytic activity can be improved by facilely adding glucose during the preparation where glucose creates a reducing atmosphere and takes away the oxygen atoms of perovskites to form more oxygen vacancies and Co³⁺. CO self-sustained combustion is favorably achieved and La_0.9Ce_0.1CoO₃-G shows the best catalytic performance. Combining the XPS, H₂-TPR, O₂-TPD and CO-TPD results, the outstanding performance of La_0.9Ce_0.1CoO₃-G is mainly ascribed to the relatively higher concentrations of Co³⁺, Ce³⁺ and oxygen vacancies. The reaction was found to follow the Langmuir–Hinshelwood (L–H) mechanism by in situ IR spectroscopy and kinetic results. Furthermore, La_0.9Ce_0.1CoO₃-G exhibits good high-temperature durability with unchanged CO conversion of 100% at 760 °C. It is suggested that the addition of glucose and the impregnation of Sr or Ce in perovskites is a feasible strategy to design industrial catalysts for CO self-sustained combustion.