He attended the Mangyongdae Revolutionary School and the Kim Il Sung Military University before starting his career in the party apparatus and the Korean People's Army.

In 1986 he was elevated to Central Committee full member, director of the KPA General Staff Operations Bureau and deputy to the Supreme People's Assembly.

In 1995, after O Jin-u's death, he was promoted to Vice Marshal and Chief of the KPA General Staff, a post he held until 2007, when he was appointed a vice-chairman of the National Defence Commission.

[5] He was replaced as Minister by Kim Jong-gak and appointed director of the WPK Civil Defense Department in April 2012.

[3] Although displaced from all significant leading posts, he was awarded the largely honorary rank of Marshal of the Korean People's Army in April 2016.