We demonstrate reduction of the dc polarizability of cesium atom Rydberg states in a 77-K environment utilizing microwave field dressing. In particular we reduce the polarizability of 52P3/2 states which have resonances at 5.35 GHz to 51D5/2, suitable for interfacing Rydberg atoms to superconducting resonators in a cryogenic environment. We measure the polarizability of the Rydberg states using magneto-optical-trap loss spectroscopy. Using an off-resonant microwave-frequency dressing field coupling 52P3/2 and 51D5/2 we demonstrate a reduction in dc polarizability of the 52P3/2 states over 80%. Experimental findings are in good agreement with a numerical model of the atom-dressing field system developed using the Shirley-Floquet formalism. We also demonstrate that the dc polarizability reduction is highly anisotropic, with near total nulling possible when the dc and dressing fields are aligned, but only a factor of 2 reduction in polarizability when the fields are orthogonal. These results may aid in stabilizing Rydberg resonances against varying dc fields present near surfaces, enabling advancement in the development of hybrid Rydberg-atom-superconducting-resonator quantum gates.