After graduating from the Department of Physics, College of Natural Sciences, Seoul National University, and receiving his Ph.D. from the University of Kentucky, Gwak became a professor of physics at Suwon National University, where he served as dean of the College of Natural Sciences and dean of the Graduate School. He has published a number of scientific books for the public readership, including Ten Scientific Revolutions that Changed the World, and has translated a number of scientific books, including Origins and The Big Bang. Gwak has also written a number of science books for children, including Why Do Things Fall to the Ground?