Improving　the　specific　capacitance　and　energy　density　of　a　fiber-shaped　supercapacitor　(FSSC)　is　critical　to　its　applications　as　an　energy　storage　device　for　advanced　smart　wearable　electronics.　In　this　paper,　a　heterogeneous　poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/reduced　graphene　oxide/molybdenum　disulfide　(PEDOT:PSS/rGO/MoS2)　fiber　was　prepared　to　achieve　a　high-performance　and　durable　electrode　for　the　FSSC.　As　indicated,　pseudocapacitive　MoS2　was　in　situ　grown　on　a　highly　conductive　acid-treated　PEDOT:PSS/rGO　assembly　with　a　hierarchical　structure.　This　structural　design　emphasizes　the　wrinkled　morphology　and　high　conductivity　of　the　PEDOT:PSS/rGO　backbone　to　maximize　the　MoS2　deposition　and　accelerate　its　electron　transfer,　which　fully　utilizes　the　pseudocapacitance　of　MoS2　and　provides　additional　capacitance　contribution　to　the　obtained　device.　Attributed　to　the　synergy,　the　prepared　fiber　electrode　in　the　FSSC　exhibits　high　volumetric/areal　specific　capacitance　(325.8　F　cm-3/405.3　mF　cm-2　at　1　A　cm-3　or　1.2　mA　cm-2)　and　excellent　rate　performance　(82%,　1-10　A　cm-3).　The　corresponding　device　shows　an　ultrahigh　volumetric　energy　density　of　6.9　mW　h　cm-3　at　a　high　power　density　of　173.6　mW　cm-3　and　an　areal　energy　density　of　8.5　μW　h　cm-2　at　215.9　μW　cm-2,　together　with　excellent　cycle　stability　and　mechanical　flexibility,　outperforming　most　of　the　previously　reported　FSSCs.　Accordingly,　the　proposed　strategy　provides　a　great　opportunity　to　develop　a　high-performance　FSSC　for　further　wearable　electronics.　©　2023　American　Chemical　Society.