The self-assembly between graphene oxide sheets and resol-type phenolic prepolymers was investigated as a method to form three-dimensional porous carbon objects with high surface areas and low densities. After freeze-drying and subsequent pyrolysis of the assembled hydrogels, ultralight graphene/carbon composite aerogels with high surface areas and porosity, good conductivity, and well-defined bulk shape were obtained. By adjusting the amount of graphene oxide and resol in the precursor mixture, aerogels with a density as low as 3.2 mg/cm3 or a surface area as high as 1019 m2/g could be prepared. It is proposed that resol molecules are first adsorbed on the surface of graphene oxide sheets, and then the surface-coated sheets are crosslinked by the polymerization of resol prepolymers. The absorption performance was evaluated for the aerogel with the lowest density. Due to the high porosity, the aerogel displayed fast absorption rates for organic solvents as well as high absorption efficiencies. The high conductivity of the aerogels permits good performance as binderless monolithic electrodes for supercapacitors.