During his fourth year, the Korean War broke out and his family was forced to evacuate to the Busan Perimeter, where he continued his schooling.

Lee later enrolled in Kyunggi High School, and one year before graduating, was admitted as the top-ranked student to Seoul National University as a chemical engineering major.

While in college, he was awarded a scholarship by the association of military wives whose husbands participated in the Korean War, enabling him to emigrate to the United States for undergraduate study.

[3] At the time of his death, Lee was widely regarded by his peers as a world-class elementary particle physicist,[4][5][6][7] that had specialized in gauge theory and weak interactions.

In 1964, Lee published an article about spontaneous symmetry breaking with his advisor Abraham Klein and contributed to the appearance of Higgs mechanism.

[12] In the meantime, Dutch graduate student Gerardus 't Hooft was working in the case of local gauge symmetry breaking in the Yang–Mills theory using the Higgs mechanism.

[17] Sheldon Glashow, Luciano Maiani and John Iliopoulos predicted charm quarks to match the experimental results.

Lee wrote an article with Mary K. Gaillard and Jonathan L. Rosner,[18] predicting the mass of the charm quarks by calculating the quantities which correspond to the mixing and decay of K meson.