The utilization of biowaste-derived porous carbon in supercapacitors has emerged as a promising approach to address the environmental concerns as well as harnessing the value-added potential of renewable biomass resources. Within this context, lignin, an abundant component of biomass and by-product of papermaking industry, presents substantial opportunities. In this paper, the Fe3C nanoparticle-embedded porous carbon (HPC-X) derived from lignin via a one-stone-two-birds strategy by used potassium ferrite (K2FeO4) as active agent. The as-prepared HPC-2 sample possesses a multi-hierarchical porous structure with a large specific surface area (2351.6 m2 g−1) and a cumulative pore volume of 1.44 cm3 g−1, where the specific capacitance of 236 F g−1 at 0.5 A g−1. The capacitance retention rate is still 94 % even after 20,000 cycles at 10 A g−1, suggesting its excellent long-time stability. This strategy paves the way for the cost-effective production of environmentally friendly and renewable carbon materials derived from biomass, and meanwhile, holds great promise for their application in advanced energy storage fields.