Visible-light boosting chemical reactions by surface plasmon resonance (SPR) have recently received much attention in photocatalysis. Although multiple types of plasmonic catalysts have been developed, the efficient utilization of SPR-induced hot-electrons remains to be a challenging task due to their ultrafast decay. In this study, structure-controlled Pd-graphene-Au nanorod nanocomposite catalysts are fabricated for maximizing hot-electron utilization in SPR-enhanced reactions. The characterization confirmed that highly dispersed Pd clusters were deposited on a homogeneous reduced graphene oxide (rGO) layer-coated Au nanorods. The catalytic activity in the Suzuki-Miyaura coupling reaction was highly enhanced under visible-light irradiation due to the SPR of the Au nanorods, whose performance was superior to that without an rGO layer. Further experimental and calculation study demonstrated that the electro-conductive rGO layer plays a crucial role as an electron mediator for promoting hot-electron transportation from Au to Pd, which resulted in the reaction acceleration.