The practical design and construction of a Stewart Platform-based unilateral universal hand-controller is presented. It is also presented that such a design concept could be implemented by developing a technical method of determining the forward kinematics of a Stewart Platform in real time. In this work, the forward kinematics of a Stewart Platform has been determined in real time using three additional displacement sensors which eliminate the computational burden of solving the forward kinematics described in nonlinear simultaneous equations. The workspace of the Stewart Platform via inverse kinematics has been analyzed numerically and used as a design guide for the determination of the mechanism dimensions such as the sizes of the upper and base platforms and the minimum and maximum lengths of the legs. The hardware of the hand-controller has been constructed and tested to demonstrate the feasibility of the design concept.