As the first Ph.D. and full-time professor of biochemistry in Korea, Lee contributed to the establishment of biochemistry as a newly organized field of study in Korea.
He began with a study of glycolysis.  In the late 1920s, the role of phosphorylated compounds in glycolysis had not yet been fully explained. Lee's work touched on early aspects of intermediary carbohydrate metabolism, which was also the subject of Nobel Prize-winning research by Otto Fritz Meyerhof, Otto Heinrich Warburg, and Hans Adolf Krebs.
Lee maintained an interest in factors affecting glucose metabolism upon his return to Korea, where he continued his research with published studies of the Korean diet.  Building upon work begun in 1928, he investigated the problem of identifying and quantifying the nutritional elements of the staple Korean diet and its effects on metabolism.  He identified nutritional sources in these foods for the healthy development of Korean children and adults during the Japanese occupation of Korea.
In addition to teaching and editing, Lee authored and co-authored at least 10 scientific papers and articles in several languages throughout his brief career. He did all of this despite working under conditions of widespread rationing at the end of World War II.