A novel electro-active polymer actuator employing the ionic networking membrane of poly(styrene-alt-maleimide) (PSMI)-incorporated poly(vinylidene fluoride) (PVDF) was developed to improve the electrical and mechanical performance of the artificial muscles. The main drawback of the previous ionic polymer-metal composite actuator was the straightening-back and relaxation under the constant voltage excitation. The present ionic networking membrane actuator overcomes the relaxation of the ionic polymer-metal composite actuator under the constant voltage and also shows much larger tip displacement than that of the Nafion-based actuator. Under the simple harmonic stimulus, the measured mechanical displacement was comparable to that of the Nafion-based actuator. The excellent electromechanical response of the current polymer actuator is attributed to two factors: the inherent large ionic-exchange capacity and the unique hydrophilic nano-channels of the ionic networking membrane. The electro-active polymer actuator of PSMI-incorporated PVDF can be a promising smart material and may possibly diversify niche applications in biomimetic motion.