A system for mounting wall panels to a wall frame or other surface, and methods for assembling and using such a system. The disclosed system may include a plurality of mounting brackets, an adjustable wall panel support mechanism coupled to the mounting brackets, and a wall panel attachment member such as a hook plate. The position and orientation of the wall panel attachment member relative to the mounting brackets may be precisely adjusted, allowing fine adjustments in the position and orientation of a wall panel after the wall panel has been installed.