<p>Land degradation caused by industrial activity, pollution, and unsustainable land use poses a significant threat to global ecosystem functions. <i>Miscanthus</i> × <i>giganteus</i> (M × g), a sterile C4 perennial grass known for its high biomass productivity and tolerance to abiotic stress, has gained increasing attention as a phytomanagement crop for restoring degraded lands. A growing body of evidence suggests that the effectiveness of M × g in these environments is strongly mediated by its interactions with rhizospheric, endophytic, and mycorrhizal microorganisms. This review synthesizes current knowledge on the structure, function, and ecological roles of microbial communities associated with M × g, with a focus on their contributions to plant growth, nutrient acquisition, stress tolerance, and contaminant degradation. Particular emphasis is placed on plant growth-promoting rhizobacteria (PGPR), endophytes, and arbuscular mycorrhizal fungi (AMF), as well as their roles in enhancing soil microbial activity, carbon sequestration, and phytoremediation of heavy metals and petroleum-based pollutants. While numerous studies have demonstrated positive microbial effects on M × g performance under controlled conditions, field-based evidence remains limited. Future research should prioritize long-term, multi-scale investigations and the development of tailored microbial inoculants for use in phytomanagement systems. By integrating plant–microbe interactions, M × g cultivation can be optimized not only for biomass production but also for ecological restoration of degraded environments.</p> Graphical Abstract <p></p>