Nickel sulfide (NiSx) was grown by atomic layer infiltration using bis(dimethylamino-2-methyl-2-butoxo)nickel(II) [Ni(dmamb)2] and hydrogen sulfide (H2S) as a metal precursor and a sulfur source. The steady-state growth rate of the film was 3.7Å/cycles at 160–190°C which was much faster compared to those by conventional atomic layer deposition method (<0.7Å/cycles). This nickel sulfide thin films were characterized by taking X-ray photoelectron spectroscopy, scanning electron microscopy, X-ray diffraction, and hall measurements. The deposited films on Si wafer was single-phase polycrystalline with multiple domains. The NiSx film grown on fluorine-doped tin oxide (FTO)-coated glass was applied to a counter electrode in dye-sensitized solar cells, which performed a high catalytic activity for the reduction of I3− to I− and the comparable cell efficiency of 7.12% with cells using conventional Pt-coated FTO counter electrode.