Refining the electromagnetic wave absorption characteristics of traditional metal–organic framework (MOF)-derived carbon composites remains a challenge because of their discontinuous conductive path. To overcome this limitation, in this work, MOF-derived hierarchical Cu9S5/C nanocomposite fibers are fabricated by electrospinning and subsequent carbonization-sulfurization process. Morphological analyses show that MOF-derived octahedral Cu9S5/C particles are evenly monodispersed inside carbonaceous fibers. This configuration creates a unique hierarchical structure, ranging from Cu9S5 particle embedding, MOF-derived skeleton, to a three-dimensional network. The optimized composite fibers (Cu9S5/C-40) exhibit extraordinary electromagnetic wave absorption performance at a low mass fraction (20 wt%): the minimum reflection loss value reaches - 69.6 dB, and the maximum effective absorption bandwidth achieves 5.81 GHz with an extremely thin thickness of only 1.83 mm. Systematic investigations demonstrate that constructing the three-dimensional conductive network to connect MOF derivatives is crucial for activating performance enhancement. The unique nano-micro hierarchical structure synergized with elaborate-configured components endows the materials with optimal impedance matching and amplifies the loss capacity of each part. This work provides a reliable example and theoretical guidance for fabricating new-generation high-efficiency MOF-derived fibrous electromagnetic wave absorbers.