This paper presents an experimental study of high-pressure chemical-looping combustion (CLC) of methane and synthesis gas using supported Cu and Ni oxygen carriers. The experiments were performed in an isothermal, fixed-bed reactor at the pressure range of 1-10 bar. The analysis showed that at elevated pressures, the reactivity of the CLC oxygen carriers deviates from that at atmospheric pressure. Formation of solid carbon was found favorable at high pressures for both oxygen carriers, though more extensively with Cu materials. An empirical kinetic model was used to capture the effect of pressure on the reduction and oxidation reactions. The objective of this work is to derive a kinetic model that can accurately capture the idiosyncrasies of high-pressure CLC, which can guide process design studies of CLC integration into power plants.