Wladimir Wladimirowitsch Klitschko (born 25 March 1976) is a Ukrainian former professional boxer who competed from 1996 to 2017. He is a two-time world heavyweight champion, having held the WBA (Super), IBF and WBO titles, as well as the IBO, Ring magazine, and lineal titles. A strategic and intelligent boxer, Klitschko is considered to be one of the greatest heavyweight champions of all time. He was known for his exceptional knockout power, using a strong jab, straight right hand and left hook, as well as excellent footwork and mobility, unusual for boxers of his size.
As an amateur, Klitschko represented Ukraine at the 1996 Olympics, winning a gold medal in the super-heavyweight division. After turning professional later that year, he defeated Chris Byrd in 2000 to win the WBO heavyweight title. Klitschko's first reign as champion ended in an upset knockout loss to Corrie Sanders in 2003, which was followed by another knockout loss to Lamon Brewster in 2004. It was during this time that Klitschko hired Emanuel Steward as his trainer, which began an eight-year partnership that lasted until Steward's death in 2012. In particular, Steward was credited with Klitschko's transition from an aggressive puncher to a more defensively-oriented boxer, much as he had done with Lennox Lewis in 1995 to 2003.