Ko Un was born into a farming family in a small village near what is now Gunsan, South Korea, in 1933. At that time, Korea had not been divided into two, but it was a colony of Japan. The Japanese colonial administration outlawed the teaching of Korean, so Ko studied Chinese classics at school (and was secretly taught Korean by a neighbor’s servant). He started to write poems at the age of twelve. In 1945 (the year Korea was liberated from Japan), he discovered a book of poems by the famous leper-poet Han Ha-un (1920-1975) lying on the wayside, and he decided to become a poet. The Korean War (1950-1953) had a major impact on his life. When the war broke out, he was forced to repair runways at a South Korean air force base. Ko saw a great deal of violence during the war, and as a result, he attempted suicide several times and suffered a nervous breakdown. He entered a Sŏn (Zen) Buddhist monastery when he was nineteen and became a student of the noted monk Hyobong. In 1958, his first poem “Pyekgyeolhaek” (“Tuberculosis”) was published in the review Modern Poetry, and in 1960, his first collection of poems, Pian kamsŏng (other world sensibility), was published.
Two years later, Ko left the monastery. He lived in Seoul for a time, and from 1963 to 1966, he taught Korean and art at a charity high school on the southern island of Cheju. During this period, Ko drank heavily. His second collection of poetry, Haebyŏn i unmunjip (seaside poems), was published in 1966. He returned to Seoul, where he continued to drink and sporadically write and publish poetry with strong nihilist themes. In the winter of 1970, his life suddenly changed after he picked up a newspaper from a barroom floor and read about a poor laborer who had committed suicide by self-immolation. Ko decided to take up the causes of civil rights and democracy, and he became a political activist and nationalist poet, helping to organize the Council of Writers for Practice of Freedom and becoming a leader in the minjung munhak (people’s literature) movement. Ko was arrested many times for protesting against the governments of presidents Park Chung-hee and Chun Doo-hwan. He was imprisoned four times (1974, 1979, 1980, 1989). The second time he was imprisoned, one of his eardrums was damaged as a result of torture. He was still able to publish several biographies, novels, and collections of poem during this time. In 1980, he was sentenced to life in prison, where he conceived of writing his most famous work of poetry, Ten Thousand Lives, which fills twenty-six volumes. Ko was released from prison in 1982 because of a general pardon, but in 1989, he was again briefly imprisoned.
In 1983, at the age of forty-nine, he married Lee Sang-wha, a young professor of English literature, and moved to Ansong, Gyeonggi-do, two hours south of Seoul. In 1985, his daughter Cha-ryong was born. After his move to Ansong, Ko has been very prolific. Since 1984, he has published more than one hundred works, as well as a seven-volume epic poem, Paektusan (Paektu mountain), about the Korean struggle for independence from Japan. From 1994 to 1998, he was resident professor in the graduate school of Kyonggi University in Seoul. Ko made numerous visits to North Korea in 2002, 2005, 2006, and 2007. In 2008, he became resident poet and professor at Dongook University in Seoul.