The origin and influence of active sites on supported copper catalysts, and their catalytic properties for ethanol conversion were investigated using Cu/SiO2, Cu2O/SiO2, and Cu/ZrO2. Diffuse reflectance infrared Fourier transform spectroscopy of adsorbed CO revealed that Cu1+ was more prevalent than metallic copper species at the Cu/SiO2 surface, and that metallic copper was the main species on Cu/ZrO2. The Cu1+/metallic Cu pair provided by Cu/SiO2 generates sites that are highly selective for the dehydrogenation of ethanol to acetaldehyde. Ethyl acetate can be formed from ethanol and acetaldehyde at ZrO2 or Cu surfaces. A combination of the Cu1+/metallic Cu pair and metallic Cu interfaced to ZrO2 is needed to efficiently transform ethanol directly to ethyl acetate and hydrogen.