In this work, activated carbon (AC) was synthesized and then modified using nickel(II) oxide and copper(II) oxide. Pure-AC, 10, 20, 30, and 40 wt % nanohybrid NiO–CuO/AC nanocomposites (χ-NC/AC NCs) were characterized using XRD, IR, EDS, surface area, and FE-SEM techniques. Furthermore, the adsorbents obtained were tested for their ability to remove hazardous Pb(II) and Cd(II) from water. The fabricated x-NC/AC NC adsorbents showed the highest adsorptive performance toward the adsorption of Pb(II) and Cd(II) from water. The 30-NC/AC NC adsorbent showed the complete removal of Pb(II) at pH = 5 and Cd(II) at pH = 7 within 30 min. Overall, the obtained superior experimental results suggest that the adsorptive performance of AC was greatly enhanced after loading hybrid metal oxide nanoparticles, so its application in water treatment is potential and applicable.