Vertical graphene nanosheets (VGN) are envisioned as supercapacitor (SC) electrode materials due to their distinct geometry and remarkable properties. Of late, the hybrid structures of graphene-transition metal (TM) or oxides were found to exhibit enhanced charge storage capacity. Herein, we report the charge storage performance of VGN-transition metal nanoparticle (Au, Ag, Cu, and Ni) hybrid electrodes. Amongst them, Ni-decorated VGN exhibited the highest enhancement, up to 3.04 mF cm-2 (121.6 F g-1) compared to 0.16 mF cm-2 (6.4 F g-1) for as-grown VGN. Further, this was corroborated by the improved electrical as well as ionic conductivity of the metal-decorated VGN structures. Additionally, the presence of metal-oxygen-carbon bonding ensured a contribution of pseudocapacitance. Ab initio calculations elucidated the extent as well as the nature of charge (e-) transfer in TM nanoparticle-VGN hybrid structures. These findings are well corroborated with the charge storage performance. A combined effect from charge transfer and pseudocapacitance on the charge storage performance of TM nanoparticle-VGN hybrid electrodes is demonstrated. A symmetric coin-cell supercapacitor device using Ni/VGN electrodes was fabricated and the sustained performance tested over 10 000 charge-discharge cycles.