This work presents a systematic composition-dependent strategy to enhance the pseudocapacitance performance of Ni_xMn_1-x@NiCo layered double hydroxide (LDH) nanocomposites synthesized via a two-step electrodeposition method. The tailored NiCo LDH nanoflower morphology is strongly influenced by the embedded Ni_xMn_1-x nanocomposites, enabling interfacial synergy and tunable electrochemical behavior. Spectroscopic analyses confirm the evolution of bonding states between the LDH matrix and Ni_xMn_1-x phases. Among the tested compositions, Ni₀.₅Mn₀.₅@NiCo LDH delivers the highest specific capacitance of 3825 F∙g⁻¹ at 1 A∙g⁻¹, while Ni₀.₇Mn₀.₃@NiCo LDH demonstrates better cycling stability and energy retention. When assembled into a hybrid asymmetric supercapacitor, the optimized electrode achieves an energy density of 166.45 μWh∙cm⁻² at 9.45 mW∙cm⁻² and maintains 134.74 μWh∙cm⁻² at 47.87 mW∙cm⁻², with 63 % capacitance retention after 2000 cycles. This study introduces a tunable design approach for high-performance energy storage devices.