Among the all emergent chemical hydrogen‐storage materials, B‐N‐H compounds, especially ammonia borane (AB) and hydrazine borane (HB), appear to be the most favorable ones owing to their advantageous features. However, hydrogen generation from these compounds in an efficient and controllable way is required for the development of new catalytic systems. We report herein a facile wet‐chemical synthesis of a new nanocatalyst, namely, monodisperse CuPt alloy nanoparticles (NPs) supported on Ketjen Black (KB‐CuPt), that exhibits unprecedented catalytic activity in the hydrolytic dehydrogenation of AB and HB with initial turnover frequencies (TOF) of 859 and 832 mol  mol_Pt⁻¹ min⁻¹, respectively, under ambient conditions. The reported TOF values are record among all Pt‐based catalysts that have been tested in both hydrolysis reactions hitherto. This study also includes detailed kinetics of the KB‐Cu₆₈Pt₃₂‐catalyzed hydrolytic dehydrogenation of both AB and HB studied on a variety of parameters.