Nanostructures decorated with noble metal nanoparticles (NPs) exhibit potential for use in highly sensitive optoelectronic devices through the localized surface plasmon resonance (LSPR) effect. In this study, Faraday rotation was significantly enhanced through the structural optimization of ferromagnetic (FM)/semiconductor composite nanostructures. Experimental and theoretical results revealed that the position of noble metal NPs significantly influenced the coupling of the LSPR-enhanced electromagnetic field with FM materials. Furthermore, nanostructures embedded with noble metals demonstrated an improved capability to efficiently use the electromagnetic field compared to other structures. The Faraday rotation of ZnO/Ag(NPs)/Fe was enhanced 58 fold compared to that of the ZnO(film)/Fe. This work provides a basis for the design of nanoarchitectures for miniaturized high-performance magneto-optical devices.