Graphene has attracted considerable attention in the scientific community for its extraordinary physical properties. The realization of a chemically cross-linked, macroscopic 3D assembly of graphene sheets having properties similar to the individual 2D sheets would significantly enhance prospects for the commercial success of this remarkable material. The integration of graphene sheets into carbonaceous aerogels, via pyrolysis of resorcinol/formaldehyde (RF) aerogels loaded with graphene oxide (GO), is a promising strategy toward this end. The huge surface area of the aerogel microstructure, combined with the outstanding electronic transport properties of the graphene network, makes such “graphene aerogels” particularly suitable as electrodes for supercapacitors. Unfortunately, the conventional base-catalyzed, aqueous synthesis of the wet precursor gels is time-consuming, requiring at least 12 hours at elevated temperature and posing a bottleneck to large-scale manufacture. In this study, we demonstrate that this problem can be significantly mitigated by means of an alternative hydrochloric acid-catalyzed synthesis with acetonitrile as the solvent, whereby wet GO–RF gels are realized within only one hour at room temperature. The process hinges on two successive half-hour ultrasonications, first with the GO and acetonitrile only, then after the addition of RF and acid, to achieve the rapid gelation. Infrared and Raman spectroscopy of the gels following supercritical CO2 drying and pyrolysis confirm graphitization of the samples with no residual carbon–nitrogen bonds from the acetonitrile or its derivatives. Galvanostatic charge–discharge tests, cyclic voltammetry, and electrochemical impedance spectroscopy attest to the positive effect of graphene on the supercapacitor performance of RF-derived aerogels, with the pyrolyzed GO–RF aerogels exhibiting 25% greater capacitance per unit area, 47% greater rate capability at 8 A/g, faster current response, lower equivalent series resistance, and capacitive behavior at higher frequencies compared to aerogels of pyrolyzed RF alone. These results, viewed in light of the unprecedented rapidity of our synthetic technique, represent a major step toward mass production of high-power electrodes for electrochemical power sources in a timely and cost-effective manner.