Kim made his debut as a fashion model in 2007. Regarded as "one to watch", he later appeared as a guest on the MBC drama series Before and After Plastic Surgery, and on family sitcom The Unstoppable High Kick. On April 21, 2008, he came out as a gay man on the tvN reality show Coming Out, a series which profiles the lives of LGBT Koreans. Shortly after the episode aired, Kim's personal webpage was inundated with messages denouncing his sexuality. Several fashion shows and television programmes cancelled his appearances, while his management company declined to renew his contract.

Kim hanged himself at his home in Jamsil, southern Seoul, on October 6, 2008. A suicide note found at the scene read: "I'm lonely and in a difficult situation. Please cremate my body." Kim's mother said that he "underwent many professional and personal difficulties following his coming-out", while police attributed his suicide to public prejudice against homosexuality. Days before taking his life, Kim wrote on his web site: "Life is like the wind. What's there to agonise over? Meetings are happy, partings are sad, everything is just a moment." His funeral service was on October 9, 2008.

Kim's death was one of several celebrity suicides in South Korea, which included the earlier deaths of actors Ahn Jae-hwan and Choi Jin-sil, and President No Moo-hyun.