Transition metal molybdates are considered a promising candidate for electrochemical applications due to their attractive chemical and physical assets. In this work, we demonstrated the preparation of the CuMoO4 nanostructures via a sonochemical approach and explored its bifunctional property of energy storage and nitrite sensor. Physicochemical and morphological characterization confirmed the formation of CuMoO4 nanostructures. Cyclic voltammograms and galvanostatic charge-discharge (CD) analyses reveal the charge storage in CuMoO4 is faradaic dominated capacitive behavior. The CuMoO4 delivered a high specific electrode capacitance of 281 F g−1 from the CD profile obtained at a current density of 0.5 mA cm−2 and exhibited good capacitance retention of 98% over continuous 3000 cycles. Furthermore, the CuMoO4//AC ASC device delivered a high specific capacitance of 100.23 F g−1 with an extraordinary energy density (31.25 Wh kg−1), power density (661.76 W kg−1) and cycle-life. Furthermore, the CuMoO4 electrode can be used for electrochemical detection of nitrite as confirmed using CV and LSV analysis. In addition, the scanning electrochemical microscopic study confirms the better oxidation current at the electrode/electrolyte surface of the CuMoO4 electrode in the presence of the nitrite solution. Overall, the obtained experimental results highlighted the importance of CuMoO4 nanostructures as an electrode material towards the next-generation electrochemical energy storage and sensing applications.