The search for nanomaterials that can offer outstanding electrochemical performances is accelerating due to the rise in demand for reliable energy storage systems. However, the body of knowledge on highly effective radioactive materials, like uranium, is still lacking. Herein, a straightforward fabrication procedure was implemented to fabricate Uranium-based hybrid electrode material, so-called uranium anchored-carbon nanotube (U-CNTx; where x represents the CNT:U ratio by weight) to be employed in ultracapacitors. A radioactive compound-based ultracapacitor cell was made for the first time, to the best knowledge of the researcher, in the rapidly developing field of energy storage devices. The physicochemical features of the fabricated U-CNTx hybrid nanostructures were examined by several characterization techniques including scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), Raman spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and the successful anchoring of the Uranium atoms on CNT architecture was confirmed as well as the morphological characteristics of the structure. With a 96.13% capacitance retention value, after 15,000 consecutive galvanostatic charge-discharge (GCD) cycles at 1.0 A g−1 in addition to a considerable specific capacitance value of 251.8 F g−1 even at a high current density value of 10.0 A g−1, the U-CNT10 electrode-based ultracapacitor cell provided the best performance parameters. The radiation doses of the assembled ultracapacitor cells were measured by a Geiger-Müller detector. The results offered that even the U-CNT10 electrode-based SC, which had the highest uranium content, had no harmful effects on human health or the environment considering its value of ∼0.1–0.3 μSv (excluded background measurement). The development of a high-performance ultracapacitor with uranium-based hybrid organic electrodes may open a new age as a result of this work.