For pseudocapacitors, the electrode material plays a vital role in the electrochemical properties. Among various electrode materials, spinel nickel cobaltite (NiCo₂O₄) has been widely investigated as an advanced electrode material owing to its better electronic conductivity (two orders of magnitude higher than conventional transition metal oxides), low cost, and high availability. With all the excitement about new electrode materials, less attention has been paid to their dynamic storage mechanism that commonly exhibit intriguing capacitive activation during charge/discharge cycling. Here, we report a simple and cost-effective approach to the synthesis of hierarchical mesporous Co₃O₄@NiCo₂O₄ nanoforests on Ni foam for supercapacitor (SC) electrode applications by a coupled one-step solution and annealing process. The synthesized electrode exhibits capacitive activation during charge-discharge cycling (from 0.73 F/cm² of the pristine state to the peak value of 1.12 F/cm² after 2000 cycles with only 1.8% loss compared to the peak capacitance after another 2000 cycles). Using ex situ TEM characterization and electrical test, We attribute such dynamic capacitive activation to (1) enlarged electroactive surface area through the formation of Co₃O₄@NiCo₂O₄ core-shell structure and (2) enhanced electrical conductivity by forming oxygen vacancies and hydroxyl groups during charge-discharge cycling. Our findings provide a scientific explanation for the capacitive activation in cobalt oxide-binary nickel cobaltite compounds, and a new design guideline for the development of capacitive activation enabled, high performance transitional oxide electrodes.