Bioderived metal–organic frameworks (bioMOFs) have attracted interest as functional materials for medical-related applications due to their biocompatibility and structural tunability. However, the integration of external stimulus responsiveness into bioMOF architectures while preserving the framework integrity remains a significant challenge. Herein, we report the synthesis and comprehensive characterization of magneto-responsive nanocomposites based on the microporous Bi(III)-ellagate bioMOF SU-101 incorporating ultrasmall magnetic nanoparticles. We demonstrate the successful integration of magnetic nanoparticles and the loading of fluorescent cargo within the MOF matrix without compromising its structural integrity. The resulting magnetic nanocomposites exhibit a well-defined magnetic response under high-frequency alternating (AMF) and low-frequency rotating (RMF) magnetic fields that enable remote modulation of thermal and mechanical effects, leading to significant cargo release and a marked reduction in cancer cell viability. Moreover, magnetic resonance imaging (MRI) relaxivity measurements confirm the potential of these nanocomposites as magnetic resonance contrast agents. Overall, these results highlight the strong potential of magnetically responsive bioMOF SU-101-based nanocomposites as multifunctional platforms for biomedical applications.