This paper presents modeling, design, and prototyping of a z-axis micro-platform actuator fabricated by MicraGEM (Micralyne GEneralized MEMS) process. With 4 crossly arranged rotational serpentine springs and 12 μm of gap between the circular disk and the bottom electrode underneath it, this platform demonstrates its simple actuation, easy control and capability of fine tuning the vertical displacement in the range of 0.5 μm to 3.0 μm through varying the applied electrical bias. Positioning sensitivity and repeatability of the platform with respect to the applied voltage have been estimated and verified by mathematical model. With proper selection of springs and their geometric parameters, high sensitivity of the z-axis platform actuators can be obtained. The proposed electrostatically actuated micro-platform will gain importance in micro-positioning for optical MEMS and microphotonic devices.