The effect of nitrogen doping in the precursor sol from different nitrogen‐bearing sources on the in situ‐grown carbon film is evaluated for use as an electrode in electrochemical capacitors. The film is developed by the electrospray coating of resorcinol–formaldehyde (RF) sol on carbon fiber paper, serving as the current collector of the capacitor and subsequent curing, solvent removal, and carbonization in situ. Ethylenediamine and melamine are the aliphatic and aromatic hydrocarbonaceous sources, respectively, that are added to RF in separate experiments. The interaction between the electrolyte ions and the electrode surface is enhanced due to the presence of nitrogen and oxygen functional groups, and is analyzed through energy‐dispersive X‐ray spectroscopy, elemental CHNS analysis, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy analyses. At the same time, the difference between the cross‐linking mechanism in the two cases leads to different pore structures at the micro‐ and mesoscales in the carbonized product, as reflected in the scanning electron microscope images and nitrogen adsorption–desorption data. The electrochemical performances of the electrodes are analyzed with regard to the two sets of results, referred earlier, and the relative importance of the pore hierarchy induced by cross‐linking is discussed.