In this study, we developed a hollow aerogel fiber out of reduced graphene oxide (rGO), with a hierarchically ordered microstructure through a three-dimensional coaxial printing methodology, that enabled a physicochemically cooperative construction process at multiscale. The rGO hollow aerogel fiber was modified by depositing polycaprolactone (PCL) and melatonin (Mel). Attributable to its elaborately designed hierarchical structure and arched alignment of two-dimensional micro-sheets, the rGO/PCL/Mel hybrid aerogel bio-fiber demonstrated remarkable structural robustness in maintaining ordered pathways and high porosity (98.5% ± 0.24%), which facilitated nerve growth in a complex survival environment in vivo. Furthermore, the excellent combination of properties such as electrical conductivity, biocompatibility, and mechanical properties (elastic modulus: 7.06 ± 0.81 MPa to 26.58 ± 4.99 MPa) led to highly efficient regeneration of well-ordered PN tissue. Systematic evaluations of nerve regeneration and muscle function recovery in a Sprague–Dawley rat model with a long nerve defect (15 mm) validated the virtually identical performance of the rGO/PCL/Mel fiber compared to autogenous nerve graft. This study suggests a promising approach to the clinical repair of long PN defects through the combined regulation of rational multiscale structure design and indispensable chemical modification of rGO aerogel-based functional nerve regeneration fibers.