Nanomaterials are playing an increasingly prominent role in recent biomedical applications, particularly due to their promising potential to combine diagnostic and therapeutic functions within a single multifunctional carrier. In this context, intrinsically luminescent silicon nanostructures offer a compelling alternative to conventional fluorophores. Their integration with magnetic nanoparticles could pave the way for the development of a traceable, multimodal platform in the field of nanomedicine. With this objective, we investigated the decoration/infiltration of light-emitting porous silicon (pSi) with iron oxide nanoparticles (FeO NPs) synthesized by pulsed laser ablation at two different liquid-gas interfaces: water-air (FeO NPs-Air), and water-argon (FeO NPs-Ar). This kind of polydispersed NPs are well-suited to filling the wide pore size range of the porous network. Moreover, their intrinsic positive surface charge enables straightforward and direct interaction with negatively charged carboxyl-functionalized porous silicon, without requiring additional surface modifications, chemical agents, or time-consuming intermediate processing steps such as the thermal oxidation or dehydration procedures reported in previous studies. The effectiveness of this simple infiltration/decoration approach-achieved through basic chemical mixing in a standard container-was successfully demonstrated by electron microscopies, Z-potential, optical, and magnetization experiments, which indicate a ferromagnetic behavior of the porous Si FeO nanocomposites (pSi + FeO NCs). The optical emission properties of the pSi + FeO NCs were maintained with respect to the bare ones, although slightly less intense and blue-shifted (about 15 nm), in agreement with the change of radiative lifetime from about 30 μs to 20 μs. Magnetic measurements reveal that pSi + FeO NCs obtained using FeO NPs synthesized at the air-water interface exhibit a weaker, noisier signal with ∼80 Oe coercivity and lower remanence. Conversely, those produced at the argon-water interface show a stronger magnetic response, with ∼170 Oe coercivity and higher remanence. Notably, the magnetic properties of the Ar-synthesized sample remained stable for months without affecting its intrinsic photoluminescence, offering a stable micro-nano optical and magnetic system for theranostics applications.