Three-dimensional (3D) porous carbon doped with heterogeneous elements serves as electrode material displaying significant advantages in the improvement of the electrochemical performance of supercapacitors (SCs). Herein, one-step carbonization and activation produced a 3D porous carbon material derived from waste jujubes. The introduction of nitrogen doping enhances the wettability of the obtained carbon while contributing to pseudocapacitance. The 3D structure offers more ion-accessible surfaces and an increased surface area (943.3 m2 g−1), thereby facilitating ion migration and the establishment of an ion adsorption layer. Consequently, the specific capacitance of prepared porous carbon is 194.2 F g−1 (at 0.2 A g−1). Furthermore, prepared carbon delivered 92.7% retention after 10,000 cycles, indicating high stability. The obtained carbon shows outstanding electrochemical performance and potential as an electrode for supercapacitors.