An approach to a reduced-head hard disk drive (HDD) involves an actuator elevator assembly for moving an actuator assembly along at least one support feature to provide a head slider access to at least two different disk media of a disk stack. The HDD includes a piezoelectric-based locking mechanism, including at least one piezoelectric actuator, movably coupled with the support feature, such that actuation of the actuator either locks or unlocks the locking mechanism relative to the support feature. When unlocked, the actuator assembly can be translated along the length of the disk stack via the actuator elevator assembly.