Nitrogen-doped carbon aerogels with hierarchically porous architectures (NHCAs) are prepared via hydrothermal treatment of cantaloupes and the following activation with potassium hydroxide. The porous structure of the obtained NHCAs can be easily tuned by adjusting the activation temperature. Among the samples, the one activated at 800 °C (NHCA-800) exhibits the highest specific surface area of 1778 m² g⁻¹ and the best electrochemical performance as both the electrode for a supercapacitor and the electrocatalyst for the oxygen reduction reaction, which is due to the co-existence of large amount of micro- and mesopores in NHCA-800.