Abstract: Carbon materials with various desirable advantages of adjustable porosity, controllable heteroatom doping and low-cost are received considerable attention to be the supercapacitor electrode. However, exploiting carbon materials with abundant micropore, high surface area and high-content dopants for applying on aqueous supercapacitor with superior energy output still becomes to be a great challenge. This work demonstrates the facile synthesis of the interconnected carbon spheres based on polyreaction between p-benzaldehyde and 2,6-diaminopyridine by adjusting the mass ratio of copolymer (PEMC) and KOH activator for achieving the enhanced capability and high energy output. The typical carbon spheres are endowed with satisfied capability and energy delivery attribute to the enhanced ion-accessible area with enriched micropore, high-level N/O functionalities and rapid ion diffusion channels in multilevel porous structure. When the mass ratio of PEMC/KOH is set as 1 : 1, the high ion-adsorptive area (2599.76 m² g⁻¹) and the codoped N/O heteroatoms of the interconnected carbon spheres facilitate the assembled symmetric device with a superior energy delivery (11.3 Wh kg⁻¹@250 W kg⁻¹) along with enhanced specific capability (303.2 F g⁻¹@0.5 A g⁻¹). This work offers a facile strategy to synthesize microporous carbon and displays their prospective application in KOH-based supercapacitor system.