To develop high-performance electromagnetic interference (EMI) shielding materials is crucial to solving the growing problem of electromagnetic pollution. Herein, we report a facile way to fabricate reduced graphene oxide/Fe₃O₄ (rGO/Fe₃O₄) hybrid-modified carbon foams for EMI shielding applications. The rGO/Fe₃O₄ was firstly synthesized via a co-precipitation method, and it was then mixed with phenol to prepare rGO/Fe₃O₄ hybrid-modified phenolic foam. The phenolic foam was further used as the precursor to fabricate rGO/Fe₃O₄ hybrid-modified carbon foam by carbonization. The fabricated rGO/Fe₃O₄ hybrid-modified carbon foam showed outstanding EMI shielding performance. The 1.5 wt% rGO/Fe₃O₄-modified carbon foam with a thickness of 3 mm exhibited an EMI shielding effectiveness (SE) of up to 63.5 dB at the X-band frequency range. In terms of specific EMI SE, these phenolic-based carbon foams with the rGO/Fe₃O₄ hybrid exhibited rather superior performance compared to the regular EMI shielding materials such as metals and conductive polymer composites (CPC). Furthermore, the rGO/Fe₃O₄ hybrid-modified carbon foam showed improved compressive mechanical properties compared with the virgin or rGO-modified carbon foam. Thus, the phenolic-based carbon foam modified with the rGO/Fe₃O₄ hybrid showed a promising future in many advanced applications where both EMI shielding and light weight are required.