Thermoelectric-enhanced air and liquid cooling of an electronic system is provided by a cooling apparatus which includes a liquid-cooled structure in thermal communication with an electronic component(s), and liquid-to-liquid and air-to-liquid heat exchangers coupled in series fluid communication via a coolant loop, which includes first and second loop portions coupled in parallel. The liquid-cooled structure is supplied coolant via the first loop portion, and a thermoelectric array is disposed with the first and second loop portions in thermal contact with first and second sides of the array. The thermoelectric array operates to transfer heat from coolant passing through the first loop portion to coolant passing through the second loop portion, and cools coolant passing through the first loop portion before the coolant passes through the liquid-cooled structure. Coolant passing through the first and second loop portions passes through the series-coupled heat exchangers, one of which functions as heat sink.