Monolithic polymer precursor of porous carbon was produced from polymerization of resorcinol–formaldehyde (RF) in the presence of cationic surfactant. The influence of concentration of the surfactant template, present in the sol–gel polymerization, on the electrochemical capacity was investigated by electrochemical impedance. It was found that a threshold concentration of surfactant is necessary to obtain sizable capacitance values. However, at higher concentrations of the surfactant, the capacitance values do not change significantly. The porous carbons have a large specific surface area (up to 671 m2/g). They also show large specific (up to 150 F/g) and volumetric capacitances (up to 130 F/cm3), in acid media. The carbon produced from the molar concentration of 0.32 M of surfactant (called carbon mesogel) was studied in detail. The products obtained from the polymerization and the thermal decomposition of the surfactant were further identified by TGA/MS analysis. The mechanical properties of the porous material show a good correlation with the values expected from the porosity present in the carbon matrix.