This paper presents a new milli-actuator using a piezoelectric quad-morph for fine head positioning in hard disk drives (HDDs). The newly proposed piezoelectric quad-morph is configured to produce a diagonal actuation, driving a parallel mechanism embodied into a suspension base plate into a lateral stroke. Finite element modeling shows the actuated suspension achieves a high sway frequency of 13 kHz and an adequate stroke. A parametric study shows that extending the lengths of the quad-morph and the parallel beams can improve both the sway frequency and the lateral stroke. The actuated suspension can also be reinforced with ribs for enhancing shock resistance and dynamic performance, yet without compromising lateral stroke generation. A prototype of the new design is fabricated and manually assembled using a bulk piezoelectric plate and a photo-chemically machined 0.1 mm thick stainless steel load beam. The driving principle of the quad-morph is tested and proven a viable and economical method to accomplish fine head positioning.