The superlubricity of sputtered MoS2 film under dry air environment was achieved by low-energy proton irradiation of 25 keV for the first time. We found that proton (H+) irradiation is able to break the Mo-S covalent bonding of as-deposited MoS2 film and leads to the formation of MoS2 nanocrystalline domains. The dangling bonds at edge planes or newly exposed edges could be passivated with hydrogen ions by bonding interaction under proton irradiation, forming hydric MoS2 nanocrystalline domains with stable S–H bind, resulting in superior antioxidant capacity of proton-irradiated MoS2 film compared to its non-irradiated counterpart. Importantly, proton irradiation can penetrate the interior of sputtered MoS2 film with thickness over 1 µm and restructure the as-deposited MoS2 film into nanocrystalline MoS2 domains to achieve superlubricity and life extension under dry air conditions. Graphical abstract