This paper presents control performances of a magnetorheological (MR) fluid-based multifunctional haptic device which is applicable to realization of in-vehicle comfort functions. By combining the functions into a single device, the proposed haptic device can transmit various reflection forces for each comfort function to a driver without requiring the driver’s visual attention. As a multifunctional haptic device, a MR knob is proposed in this work and devised to be capable of both rotary and push motions with a single knob. Based on the optimally determined design parameters to maximize a control torque, the proposed haptic device is manufactured. And in-vehicle comfort functions are constructed in virtual environment which makes the functions to communicate with the haptic device. Subsequently, a feed-forward controller using torque/force maps is formulated for the force tracking control. Control performances such as reflection force of the haptic device are experimentally evaluated via the torque/force map-based feed-forward controller.