Nitrogen-doped porous carbon (NCs) have been synthesized by direct pyrolysis of a mixture containing melamine, iron nitrate and ethylene diamine tetraacetic acid (EDTA). Both the addition of melamine and the carbonization temperature play critical roles in the formation of the unique structure. The results demonstrate that NC-700 shows the best electrochemical performance compared to the other samples. High specific capacitance (275 F g⁻¹ at 0.3 A g⁻¹) is obtained in 6 M KOH, and the capacitance still maintains 202 F g⁻¹ when tested at 10 A g⁻¹ (ca. 73.5% capacitance retention). Moreover, the NC-700 also possesses good cycling stability with only a loss of 2.0% after 10 000 cycles at 10 A g⁻¹. The facile preparation method and good electrochemical performance render NCs a promising candidate for supercapacitor applications.