Advanced logic and physical synthesis tools provide a vast number of tunable parameters that can significantly impact physical design quality, but the complexity of the parameter design space requires intelligent search algorithms. To fully utilize the optimization potential of these tools, we propose SynTunSys, a system that adds a new level of abstraction between designers and design tools for managing the design space exploration process. SynTunSys takes control of the synthesis-parameter tuning process, i.e., job submission, results analysis, and next-step decision making, by automating a key portion of a human designer's decision process. We present the overall organization of SynTunSys, describe its main components, and provide results from employing it for the design of an industrial chip, the IBM z13 22nm high-performance server chip. During this major design, SynTunSys provided significant savings in human design effort and achieved a quality of results beyond what human designers alone could achieve, yielding on average a 36% improvement in total negative slack and a 7% power reduction.