He served as commander of the Korean People's Navy.

In May 1977, Kim Yun-sim served as division commander of the Korean People's Army, and was appointed commander of the West Sea Fleet in July 1991.

In April 2002, he was promoted to captain of the People's Army.

In December 2007, he withdrew from the position of naval commander.

In February 2012, he received the Kim Jong-il Medal.