Spinel ferrites have recently received significant attention due to their high potential for environmental remediation. We herein report highly stable Cu−Mg substituted zinc ferrites, which were achieved for the first time using a sonochemical method. The phase purity and chemical composition of as‐synthesized ferrites were confirmed by using X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). The size, shape, magnetic properties, and morphology of ferrites were characterized by using Transmission electron microscopes (TEM), Energy Dispersive X‐Ray Analysis (EDX), and Vibrating Sample Magnetometer (VSM). The catalytic performance of the synthesized ferrite was observed in the reduction of aqueous 4‐nitrophenol to 4‐aminophenol with NaBH4. The maximal reduction attained by the Zn1‐xCu0.5xMg0.5xFe2O4 nanoferrite (1.5 min) was significantly impactful than that of other ferrites. The rate constant for the reduction of 4‐nitrophenol was determined to be 0.502 min−1, which was higher than previously reported literature values, and the reduction followed pseudo first‐order kinetics. The cation distribution, crystallinity, and morphology of Zn1‐xCu0.5xMg0.5xFe2O4 were found to be responsible for its higher catalytic activity. Further, this research has the potential to be useful in environmental remediation and offers new findings on mixed ferrite.