Magnesium ferrite (MgFe2O4) is one of the most significant spinel ferrites. It is a soft magnetic n-type semiconductor material with a small band gap (2.18 eV). A room temperature synthesis technique of electrodeposition has been utilized to fabricate magnesium-iron-oxide thin films. Electrodeposition is selected as it is fast, convenient, non-vacuum, reliable, environmentally friendly, controllable and cheap. In this research work, magnesium-iron-oxide thin films have been successfully synthesized on copper substrates. The deposition time is kept 20 min fixed, while the in-situ oxidation time ranged from 10 min to 30 min with a 5 min interval. The structural, morphological, dielectric and magnetic properties are studied. The X Ray Diffracaction (XRD) pattern has revealed a single-phase cubic spinel formation. The phase-pure of MgFe2O4 at 30 min oxidation times has larger crystallite size 25.04 nm. The Fourier Transform Infra Red Spectroscopy (FTIR) analysis has revealed the evolution of the spinel bands at 555 cm−1 and 990 cm−1 of magnesium-iron-oxide thin films. A smooth characteristic porous structure has been observed in the thin film at 30 min. The dielectric constant (ɛ) of 6.76 and the loss tangent (tanδ) of 0.08 at log f = 5 is observed for 30 min oxidation time. The magnetic hysteresis curve (M-H) exhibits strong ferromagnetic behavior for all the magnesium-iron-oxide thin films. The remarkable findings of the MgFe2O4 thin film at 30 min makes it a potential candidate for electronic and spintronic devices.