This study reports the development of a heterostructured molybdenum disulfide (MoS2)@vertically aligned graphene fiber (MoS2@VA-GF) for high-energy-density electrochemical supercapacitors. The MoS2 nanosheets are decorated on vertical graphene fibers through C–O–Mo covalent bonds, creating a unique structure with well-defined, large faradic activity, and high-exposed surface/porosity. This architecture efficiently facilitates ionic pathways, interfacial electron mobility, and pseudocapacitive accessibility, leading to a high gravimetric capacitance of 564 F g−1 in 1 M H2SO4 electrolyte. The MoS2@VA-GF-based solid-state supercapacitors exhibit a high energy density of 45.57 Wh kg−1, good cycling stability (89.5% capacitive retention after 20,000 cycles), and deformable/temperature-tolerant capability. These properties enable practical applications such as powering multicolored optical fiber lamps, wearable watches, electric fans, and sunflower toys. The findings provide a robust platform for advanced fiber electrodes in smart textile energy storage and wearable industries.This study reports the development of a heterostructured molybdenum disulfide (MoS2)@vertically aligned graphene fiber (MoS2@VA-GF) for high-energy-density electrochemical supercapacitors. The MoS2 nanosheets are decorated on vertical graphene fibers through C–O–Mo covalent bonds, creating a unique structure with well-defined, large faradic activity, and high-exposed surface/porosity. This architecture efficiently facilitates ionic pathways, interfacial electron mobility, and pseudocapacitive accessibility, leading to a high gravimetric capacitance of 564 F g−1 in 1 M H2SO4 electrolyte. The MoS2@VA-GF-based solid-state supercapacitors exhibit a high energy density of 45.57 Wh kg−1, good cycling stability (89.5% capacitive retention after 20,000 cycles), and deformable/temperature-tolerant capability. These properties enable practical applications such as powering multicolored optical fiber lamps, wearable watches, electric fans, and sunflower toys. The findings provide a robust platform for advanced fiber electrodes in smart textile energy storage and wearable industries.