Developing an active and stable metal single-atom catalyst (SAC) is challenging due to the high surface free energy of metal atoms. In this work, we report that tailoring of the 5d state of Pt-1 single atoms on Co3O4 through strong electronic metal-support interactions (EMSIs) boosts the activity up to 68-fold higher than those on other supports in dehydrogenation of ammonia borane for room-temperature hydrogen generation. More importantly, this catalyst also exhibits excellent stability against sintering and leaching, in sharp contrast to the rapid deactivation observed on other Pt single-atom and nanoparticle catalysts. Detailed spectroscopic characterization and theoretical calculations revealed that the EMSI tailors the unoccupied 5d state of Pt-1 single atoms, which modulates the adsorption of ammonia borane and facilities hydrogen desorption, thus leading to the high activity. Such extraordinary electronic promotion was further demonstrated on Pd-1/Co3O4 and in hydrogenation reactions, providing a new promising way to design advanced SACs with high activity and stability.