Magnesium oxide nanoparticles (MgO NPs) without and with Ca, Eu dopant were synthesized by using the W. somnifera leaf extract through the low temperature green combustion method. The detailed analytical characterizations such as Powder X-Ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Transmission Electron Microscopy (TEM), Fourier Transform-infrared Spectra (FTIR), etc. have been carried out for the obtained NPs. The PXRD patterns confirmed the formation of the Periclase structure with the cubic phase whereas the SEM and TEM results revealed the agglomerated roughly spherical granular structures of about 50–70 nm in size. FTIR spectra confirmed the formation of the metal–oxygen stretching vibration (Mg-O) bond at 419 cm−1. Multifunctional studies were performed over the MgO NPs for their electrochemical impedance, cyclic voltammetry and antibacterial activities.