Chang earned an undergraduate degree from Seoul National University in 1974, and pursued a doctorate at the University of Texas at Austin. After completing his studies in 1979, Chang undertook research in La Jolla and Carlsbad, California. In 1986, Chang was appointed a professor of physics at the Korea Advanced Institute of Science and Technology, and concurrently held a research professorship at New York University's Courant Institute of Mathematical Sciences from 1988. He became a research physicist at Princeton Plasma Physics Laboratory in 2011, and retained a joint professorship at KAIST. While at New York University, Chang was elected to fellowship of the American Physical Society in 2006, "[f]or seminal and pioneering contributions in neoclassical, rf-driven, and basic transport theories, and for his leadership in plasma edge simulation in toroidal magnetic confinement devices."