Aerobic activated sludge process (AAS) is the most widely used biological wastewater treatment process, but its treatment efficiency is limited by low dissolved oxygen (DO) concentration and mass transfer rate. Herein, high-gravity technology (Higee), an efficient mass transfer enhancement technique, was used to enhance AAS to improve municipal wastewater treatment efficiency. Higee-enhanced AAS (Higee-AAS) rapidly reduced chemical oxygen demand and NH3-N to below the discharge limits, and it was effective in removing the compounds (e.g., aliphatic/proteins) that were stubborn in AAS. In Higee-AAS, DO increased dramatically, and activated sludge became more dispersed with smaller particle size, which facilitated contact between oxygen and sludge, improving oxygen utilization rate and microbial activity. The increases in extracellular polymeric substances and relative abundance of microorganisms (Bacteroidete, Nitrosomonas, and Nitrospira) in Higee-AAS were helpful to remove pollutants. Higee-AAS can effectively improve wastewater treatment efficiency, and it has potential as a new wastewater treatment technology.