Design of advanced highly porous heteroatom-doped carbon is desirable for their wide presence in applications like electrochemical energy storage systems, gas adsorption, and separation processes. In this work, porous nitrogen-doped carbon was developed from ethylenediamine via an in situ self-doping solvothermal process followed by pyrolysis and KOH activation under high temperature. Micropore-rich nitrogen-containing carbon materials were prepared through variation of the KOH/C ratio during activation and their electrochemical performance in alkaline electrolyte as well as CO₂ sorption behaviour was evaluated. The porous carbon developed using KOH/C ratio of 2 delivered highest supercapacitor performance in 6 M KOH achieving high specific capacitance of 353 F g⁻¹ with 1 A g⁻¹ of current due to its high pore volume and micropore rich surface. The functionalized carbon delivered CO₂ uptake capacities of 4.48 and 3.0 mmol g⁻¹ under temperatures of 273 and 298 K, respectively, at 1 bar pressure with a good CO₂/N₂ selectivity of 20.58 and CO₂/CH₄ selectivity of 3.83. The existence of nitrogen functional groups, high surface area, and micropore-rich porous structures may be the essential reasons behind superior electrode performance and CO₂ capture capacity of the material. This work hopefully offers a simple development of N-doped carbon for effective energy storage and CO₂ adsorption systems.