A disk drive with a dual-stage actuator has a moving-slider rotary piezoelectric microactuator as the secondary actuator. The microactuator has a substrate attached to the disk drive suspension. A rotatable frame that supports the slider is attached to a fixed post on the substrate by relatively stiff torsional springs. A piezoelectric driver having a fixed end attached to the substrate provides bidirectional linear displacement of its movable end. The microactuator includes a displacement amplification mechanism. In one embodiment an arm or connecting rod is located between the driver's movable end and the frame. A linkage between the movable end of the driver and a first end of the connecting rod translates the linear displacement of the driver to amplified orthogonal linear displacement of the rod. The second end of the rod is attached to the rotatable frame at a radial distance to cause rotary movement of the frame, and thereby cross-track displacement of the read/write head on the slider.