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An essential challenge faced by pseudocapacitive electrode materials is insufficient charge storage capability with high intrinsic electrical resistance and structural instability. With an exponential increase in the demand for a pollutant-free environment, ternary metal compounds are being extensively explored as an attractive solution to these problems. Herein, we have addressed a solution to the above-listed issues by synthesizing novel and binder-free NiMnCo layered double hydroxide (NiMnCo-LDH) nanosheets on Fe-substituted NiCo2O4 (FexNi1−xCo2O4) nanorods supported on nickel foam via a facile hydrothermal method followed by chemical bath deposition. The highly defined and well-distributed porous Fe-substituted NiCo2O4 nanorod structure integrated with the ternary NiMnCo-LDH nanosheets provide ultra-fast kinetics of charge transfer, increased charge storage capacity, and high structural stability. The nanocomposite electrode delivers a high specific capacity of 281 mAh/g at a scan rate of 5 mV/s (265 mAh/g at 1 A/g) with a capacitance retention of 92% after 5000 cycles at 2 A/g. The effect of Fe in NiCo2O4 is further validated by performing density-functional theory (DFT) calculations to obtain atomic insights on electrical conductivity using the density of states (DOS) and band structures. Finally, a symmetric supercapacitor based on FexNi1−xCo2O4@NiMnCo LDH was assembled which delivered an impressive energy density of 105 Wh/kg and a power density of 1112 W/kg, proving FexNi1−xCo2O4@NiMnCo-LDH as an electrode material to be used for applications of energy storage. [ABSTRACT FROM AUTHOR]