In this study, three-dimensional porous magnesium ferrite/titanium dioxide/reduced graphene oxide (MgFe₂O₄-GM/TiO₂/rGO (MGTG)) was successfully synthesized via green and hydrothermal-supported co-precipitation methods using the extract of Garcinia mangostana (G. mangostana) as a reducing agent. The characterization results indicate the successful formation of the nano/micro MgFe₂O₄ (MFO) and TiO₂ on the structure of the reduced graphene oxide (rGO), which can also act as efficient support, alleviating the agglomeration of the nano/micro MFO and TiO₂. The synergic effects of the adsorption and photodegradation activity of the material were investigated according to the removal of crystal violet (CV) under ultraviolet light. The effects of catalyst dosage, CV concentration, and pH on the CV removal efficiency of the MGTG were also investigated. According to the results, the CV photodegradation of the MGTG-200 corresponded to the pseudo-first-order kinetic model. The reusability of the material after 10 cycles also showed a removal efficiency of 92%. This happened because the materials can easily be recollected using external magnets. In addition, according to the effects of different free radicals ·O₂^?, h⁺, and ·OH on the photodegradation process, the photocatalysis mechanism of the MGTG was also thoroughly suggested. The antibacterial efficiency of the MGTG was also evaluated according to the inhibition of the Gram-positive bacteria strain Staphylococcus aureus (S. aureus). Concurrently, the antibacterial mechanism of the fabricated material was also proposed. These results confirm that the prepared material can be potentially employed in a wide range of applications, including wastewater treatment and antibacterial activity.