Three-dimensional (3D) kenaf stem-derived porous carbon (PC) is considered to be a promising low-cost supporting material for application in energy storage devices. In this report, a simple and industry-scalable approach to prepare the hybrid (MnO2/3D-PC) of nanostructured MnO2 and 3D-PC has been developed. Such porous structures of the 3D-PC not only provided a conductive network to enhance the charge transport and mass transfer in the electrochemical process but also achieved a large MnO2 mass loading capacity of 11.5mg/cm2, which resulted in a high areal capacitance of 2.77 F/cm2 at a scan rate of 1mV/s. A specific capacitance of 416 F/g was obtained based on the mass loading of 2.52mg/cm2 at scan rate of 1mV/s. Furthermore, the symmetrical supercapacitor based on the MnO2/3D-PC exhibited outstanding cycle performance with only 14% degradation after 1000 cycles under a large specific current density of 16mA/cm2. This research demonstrated that the 3D-PC was a good potential supporting material in energy conversion and storage devices.