In this article, we report a novel linear-to-rotary motion converter that employs a single-crystal 0.71Pb(Mg1/3Nb2/3)O-3-0.29PbTiO(3) (PMN-29PT) (PMN-29PT ) stack actuator and asymmetric compliant mechanics for flexural hinges. This unique motion converter is compact, economical to fabricate and has the capacity to be utilized in small-scale applications. The linear-to-rotary motion converter prototype was designed and fabricated using a seven-bar linkage kinematic model. Additionally, compliant mechanics at flexural hinges were used in place of conventional revolute joints. The converter consists of a stack actuator and a structural mechanism, including flexural hinges and a pivot hinge to convert linear motion to rotary motion. To determine the feasibility of the mechanism design and to estimate the accurate rotational motion of the designed converter, numerical simulations utilizing COMSOL Multiphysics 4.3 and experimental validation were performed by evaluating the displacement of the stack actuator and the rotational angle of the linear-to-rotary motion converter according to the changes of driving voltages. The experimental results show that the linear-to-rotary motion converter can produce a rotation angle of 1.52 degrees at an input voltage of 900 V. The unique linear-to-rotary motion converter design proposed here can be applied to various engineering fields, instead of existing mechanical linear-to-rotary mechanisms, due to the advantages in compact size and precise control.