Carbon materials with various structures have been investigated for use as electrode materials in supercapacitor devices. Therefore, this study aims to investigate the electrochemical performance of activated carbon nanofibers (ACNF) as a carbon electrode for supercapacitor applications in different aqueous electrolytes. Acidic (1M H₂SO₄), neutral (1M Na₂SO₄), and alkaline (1M KOH) electrolytes were used to investigate the electrochemical performance of the ACNF electrode. The morphology and elemental composition of the ACNF were studied using a scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). Furthermore, the Brunauer Emmet Teller (BET) and X-ray diffraction (XRD) were used to investigate the texture and structure of ACNF. The ACNF has fibers of diameter ranging from 45 nm to 56 nm. The ACNF has a high specific capacitance as well as a high energy density. Hence, the optimized aqueous electrolyte for the ACNF-based carbon electrode in the supercapacitor was determined to be in 1M H₂SO₄, with a specific capacitance of 214 F g^-1 when compared to commonly used neutral (1M Na₂SO₄) and alkaline (1M KOH) electrolytes. This discovery is expected to boost the development of electrode materials for supercapacitor devices.