In 1937, at the age of 14, he traveled to Japan and became a pupil of Kitani Minoru. Japanese reading of his name was Cho Nan-Tetsu. He was the first professional from Korea, at age 18. He returned to Korea in 1943 (1944?) and in 1945 founded the Hansung Kiwon, the predecessor of the modern Hankuk Kiwon (Korean Go Association).
For a long time he was the strongest player in Korea, winning the Kuksu title nine times in a row (1956-1964), the Chaegowi title seven times in a row (1959-1966), the Paewang title four times in a row (1959-1962), the Myeongin twice (1968, 1970). His lifetime total was 30 titles.
In 1982, he reached the rank of 9-dan.
He died at 83 of old age in his home. He was survived by his wife, a son, and two daughters. After his death, he was posthumously honored by the president of Korea, Roh Moo-hyun, who sent a medal and a floral tribute.