Various polymer nanocomposites exhibiting elecro-conductivity along with flexibility were successfully fabricated by construction of the graphene-based three-dimensional (3-D) mesoporous skeleton platform derived from 3-D interconnected framework architecture constituted with two-dimensional (2-D) graphitic nanosheets, and the subsequent infiltration of polymer into pore volumes of the skeleton platform. The mesoporous 3-D skeleton platform of graphene has been easily constructed by the aggregation of graphene-coated polystyrene (PS) hybrid spheres prepared through ionic interacton between anionic graphene nanosheets and cationic PS nanospheres, and the subsequent thermal removal of polymer components, which made it possible to provide well-made pathways for electron transport as well as empty pores for the following infiltration of polymer matrix component. When a flexible polymer such as PVDF-HFP was chosen as a polymer matrix component entering into pore volumes of the graphene skeleton platform, the graphene/polymer nanocomposite tended to exhibit interesting behavior of electrical conductivity, which is comparable to that of neat graphene skeleton platform, and also maintained the initial value even under half-folding condition, evidencing excellent structural stability of the graphene skeleton. Furthermore, it was found that exchange of polymer matrix does not significantly alter the electrical conductivity of nanocomposite, confirming again the performance of 3-D graphene skeleton employing interconnected framework architecture as electron transport pathway. The ability to embed 3-D graphene skeleton into polymer matrix is a great opportunity to impart high electrical and mechanical properties to polymer composite formulation.