The development of nonprecious electrocatalysts with high hydrogen evolution reaction (HER) activity for water splitting is highly desirable but remains a significant challenge. Molybdenum disulfide (MoS 2 ) has been demonstrated as a good candidate; however, insufficient active sites along with poor conductivity significantly hinder the overall efficiency of MoS 2 . In this work, we present a method to activate commercial MoS 2 by high concentration nitrogen doping via a facile high-temperature treatment routine. The dominant N-doping mechanism is demonstrated to be an appropriate one-to-one substitution of sulfur atoms, which is confirmed by the approximate constancy between the atomic ratio of Mo/(S + N) and stoichiometric number of original MoS 2 . By controlling the activation time and temperature, the concentration of the doped nitrogen atoms can be tuned up to 41 atom %. The HER activity of the as-prepared materials was evaluated as electrode materials, showing that the catalytic activity is strongly correlated with the doped nitrogen concentration, and the catalytic current density of N-doped MoS 2 can reach 15 times higher than that of the pristine MoS 2 . The prominent improvement of HER performance for N-MoS 2 can be attributed to rich active sites, higher electron concentration around active sites, and ameliorative conductivity induced by N incorporation. The facile and controllable approach to activate MoS 2 for achieving high-level N-doping developed in this study can shed significant light on the preparation of heteroatoms-doped electrocatalytic materials.