Porous carbon derived from biomass represents pivotal electrode materials for electric double-layer capacitors (EDLCs). However, their applications are limited by the low pore utilization and low withstanding voltage (< 2.7 V), which largely hinder the energy density (Eg) of SCs. In this study, fulvic acid-derived porous carbons (FPs) were synthesized through the self-assembly and KOH activation strategy by employing fulvic acid (FA) as the precursor and cationic surfactant PDDA as the soft template. The electrostatic forces between FA and PDDA enable the structural orientation of FA, leading to the formation of stable layered liquid microcrystals. Besides, under the activation process, the decomposition of PDDA contributes to the interconnected pores in FPs. Thus, the obtained sample FP1 exhibits a high specific surface area (2593 m2 g− 1) and high mesopore ratio (48%). Moreover, low oxygen content and stable surface composition promote the withstanding voltage of FPs. In the TEABF4/ PC electrolyte, the sample FP1 is capable of a high voltage of 3.0 V, high-rate capability C10/0.05 of 76.3%, and high energy density of 39 Wh kg− 1.