In the current state-of-the-art machine learning based real-time control of large complex networks such as electric power systems is largely bottlenecked by the curse of dimensionality. Even the simplest control designs demand numerical complexity to accomplish. The problem becomes even more challenging when the network model is unknown, due to which an additional learning time needs to be accommodated. This project will take a new stance for solving this problem, and develop a suite of hierarchical or nested machine learning-based schemes that take advantage of various forms of physical redundancies in the network dynamics to learn only the most important traits of its behavior instead of wasting time in learning minor traits that may improve the closed-loop performance only by a small amount. This selective learning approach will reduce learning time by several orders of magnitude, making real-time control more tractable and more implementable. Products will include numerical algorithms that are applicable across a wide range of machine learning based control. In terms of societal impact, the project is strongly envisioned to bring control theorists closer to data scientists so that these two research communities can work together, and answer important questions such as: why the value of big data has traditionally been under-utilized in controls, what new dimensions can control theory gain from machine learning and vice versa, and what primary analytical and experimental tools are needed to make this marriage more successful. The research will also support the cross-disciplinary development of a diverse cohort of PhD and undergraduate students, and the development of a graduate-level course on the applications of machine learning in control.