Graphitic carbon nanofibers (CNFs) decorated with ZnO nanoparticles (NPs) were synthesized by chemical co-precipitation method. This report demonstrates an effective strategy to intrinsically improve the conductivity and supercapacitive performance of the hybrids by inducing oxygen vacancies. Oxygen deficiency-related defect analyses were performed qualitatively as well as quantitatively using Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. All of the analyses clearly indicate an increase in oxygen deficiencies in the hybrids with an increase in the vacuum-annealing temperature. At a current density of 3 A g-1, the hybrid electrode exhibited higher energy density (119.85 Wh kg-1) and power density (19.225 kW kg-1) compared to a control ZnO electrode (48.01 Wh kg-1 and 17.687 kW kg-1). The enhanced supercapacitive performance is mainly ascribed to the good interfacial contact between CNF and ZnO, high oxygen deficiency, and fewer defects in the hybrid. Our results are expected to provide new insights into improving the electrochemical properties of various composites/hybrids. (1) Mefford, J. T.; Hardin, W. G.; Dai, S.; Johnston, K. P.; Stevenson, K. J. Nat. Mater. 2014, 13, 726-732. (2) G.R. Dillip, A.N. Banerjee, V.C. Anitha, B. Deva Prasad Raju, S.W. Joo, and B.K. Min, ACS Appl. Mater. Interfaces 8, 5025 (2016). (3) G.R. Dillip, A.N. Banerjee, V.C. Anitha, S.W. Joo, B.K. Min, S.Y. Sawant, and M.H. Cho, ChemPhysChem 16, 3214 (2015).