He also practiced in the Korean martial art, Taekwondo and attained the rank of 9th degree black belt.
He attended the Tae Jon High School, where he intensively studied martial arts, training under Han Sang-yul.
After graduating from high school, he attended the Korean Yudo College, now known as Yong-In University from 1954 to 1958 (which is specialized in martial arts) in order to become a judo teacher.
At the same time, Kim was also contacted by the Korean Air Force for the same purpose, which makes him the first judoka to become an instructor at the Korea Military Academy.
It was also in the Korea Military Academy that he was called "The Tree" for the first time, by his students, because they considered that it was impossible to take him to the ground during judo's sparring (randori).
[5] In 1972, Kim became the judo instructor at the University of Pittsburgh after being introduced to the Dean of their Athletic Department by his student Gary Goltz.
This surgery started to become problematic as Kim had many staph infections which forced him to stay in hospital for prolonged periods.
[7] First, Kim was very skeptical of the idea on getting a heart transplant, however his lifelong student Gary Goltz (who was both a senior healthcare industry executive and past President of the United States Judo Association) eventually convinced him, arguing that the influence Kim had on him growing up was too important to deprive others of its benefit particularly his grandsons for him to give up.
[8] Of the twelve hundred procedures performed at University of Pittsburgh Medical Center since 1980, only fifteen to twenty fell into this category.
Although the donor heart was less than perfect as it exhibited signs of a cardiovascular disease, Kim chose, in his words, "to take a chance.”[9] On June 28, 2008, the surgery started on Saturday morning and took more time than normally as the operation lead to a bleeding problem.
[10] Despite a pessimistic prognosis, Kim and his family and his students did not give in and finally made it to the University of Pittsburgh Medical Center and a team of surgeons agreed to lead the transplant after a final battery of tests, the medical staff declared that given his good physical condition he was a healthy enough candidate for the transplant.
[13] During his absence, touched by the illness of their instructor, more than fifty of his students at Kim's Martial Arts and Fitness studio in Brentwood decide to renovate his dojo.
As a group effort, they wanted to do something for their teacher and purchased and installed new flooring and mats as well as a new computerized recording system.
His dojo appears like a real family to him because he keeps in touch with his old students more than thirty years after taught them martial arts.