Started work as a press and lathe operator in 1979. Headed the trade union of Tong-Il Heavy Machinery in 1985. Became Secretary General of Korean Trade Union Congress in 1993, and from 1999 held the position of President of the Korean Metalworkers Federation.
Founding member of the Democratic Labor Party, and a member of the central committee, he has been the head of the Gyeongsangnam-do province office of the DLP since 2004, and became party president in 2006.