Lee, who was the top pupil of "head-butt master" late Kim Il, made his pro wrestling debut in 1975 and rose in the scene after winning the heavyweight championship belt at the World Wrestling Association. When the popularity of pro wrestling started going down in South Korea in the 1980s, Lee tried to revive the industry by actively performing in the ring and appearing on television shows.

Lee also made headlines in 2009 and 2010 when he faced US mixed martial arts fighter Bob Sapp.

He officially retired from the ring in 2015 but had been actively engaging in the development of South Korea's pro wrestling industry.

Lee had surgery and overcame gallbladder cancer in 2013, but the same type of cancer recently returned, forcing him to stay hospitalized. (Yonhap)