We report a micro actuator platform that produces large deflection and high-force movements of multiple membrane arrays to control microfluidic channels constructed atop, by utilizing electromagnetic force and hydraulic deflection amplification. Additionally, a high-elongation polymer, Latex, is introduced as an actuator membrane to accommodate highly enhanced membrane deflection. The fabricated actuator platform (20×20×8 mm3) produced the maximum membrane deflection of 441um and actuation force of 53.9mN at an operation voltage of 14V utilizing a 120μm-thick Latex membrane. It successfully demonstrated leak-free valving (open/close) operation up to 2Hz against liquid flow pressure of 0.7kPa in actual microfluidic channels with various geometries (width/height are 500/51μm and 1500/202μm). Thus, this system obviates the need for external fluidic sources, such as highly-pressurized gas cylinders or syringe pumps that have prohibited the true `miniaturization' and `portability' of typical lab-on-chips.