In this work, one pot synthetic methodology was developed, wherein simple purging of H2S gas into a solution/dispersion of polyoxometalates in the absence as well as presence of reduced graphene oxide (rGO) at room temperature resulted in the formation of MoSx and MoSx‐rGO composites. Powder XRD, TEM, EDS elemental analysis, TGA, and XPS study reveal that as prepared samples mainly consist of nanocrystalline MoS3 particles whereas annealed samples mainly contain few layers of MoS2 nanosheets. Annealed samples exhibit better electrocatalytic activity towards hydrogen evolution reaction (HER) as compared to the as‐prepared samples. Among all the annealed samples, MoS2‐rGO nanocomposite exhibits superior catalytic activity for HER with lower onset overpotential and higher current density, as compared to other conventional MoS2. The Tafel slope of 41.7 mV/decade for MoS2‐rGO nanocomposite signifies that MoS2 catalyzed HER follows the Volmer‐Heyrovsky mechanism wherein, electrochemical desorption of hydrogen is the rate‐limiting step. Moreover, the integration of few layers of MoS2 and rGO enable remarkable long‐term electrochemical stability and showing negligible change in the current density even after 3000 cycles.