He was born in Busan in 1962. A former physician who graduated from Inje University College of Medicine, he joined the Salesian Order later in life after completing his military service as a military doctor. Following 10 years of training and theological education, including studies in Rome, he was ordained a priest in 2001. Immediately after his ordination, he was sent to Tonj, South Sudan, where he established a hospital to treat residents dying of malaria and cholera, as well as people with leprosy. He traveled to remote villages to provide medical care, founded a school (Don Bosco School) for children who had no access to education, and taught music (brass band) to help heal children traumatized by war. The people of Tonz called him “Father Joli,” combining his baptismal name, John, with his surname, Lee.

In 2005, he was awarded the 7th Inje Character Award in recognition of his dedicated service. In 2008, while on leave in Korea, he was diagnosed with stage 4 colon cancer and, unable to return to Tons, received the 2nd Korea-U.S. Proud Physician Award while battling the disease; he passed away on January 14, 2010, at the age of 48.

His life was chronicled in several film projects, including the ary *Don’t Cry, Tons* (2010), which generated a significant response. In 2008, while on vacation in Korea, he was diagnosed with stage 4 colon cancer and was unable to return to Tons; after a long battle with the disease, he passed away in January 2010. His life was chronicled in several film projects, including the ary “Don't Cry, Tones” (2010), which generated a huge response.​