Throughout his professional career, Lennox suffered just two losses, both of which he avenged in re-matches, both by knock-out.
Born in London to Jamaican-born parents, the family moved to Kitchener in Ontario in 1977 when he was 12. He became an outstanding amateur boxer, winning the world junior heavyweight title in 1983 and the Olympic gold medal in Seoul five years later, where he beat future world heavyweight champion Riddick Bowe in the final.
He turned professional in 1989, winning his first 21 fights. In 1992 he knocked out Donovan Ruddock to become No 1 in the World Boxing Council rankings and he was eventually declared champion a year later. Although he lost the title to Oliver McCall in 1994, he won it back from him in a re-match in 1997. He became undisputed world champion after defeating Evander Holyfield in November 1999.
The most celebrated fight in which Lennox took part came in June 2002, when he defended his title against Mike Tyson. The fight was anticipated as a classic between Tyson’s brawling style and Lewis’ more skilful approach. In the end it turned out to be a one-sided confrontation as Lewis used his jab and superior reach to score a dominant eighth round knock-out victory over ‘Iron Mike’. The fight was the highest-grossing event in pay-per-view history at the time, generating US$106.9 million.
In another famous fight in May 2003, he fought the No 1 contender Vitali Klitschko. Lennox struggled in the early rounds, but opened a cut above Klitschko's eye with a right cross in the third round. Before the start of the seventh round, the doctor advised that the fight should be stopped in Lewis’ favour, although Klitschko was leading at the time.
Lewis eventually announced his retirement in February 2004. When he left the ring, his record was 41 wins, 2 losses and 1 draw, with 32 wins by knockout. He became a Laureus World Sports Academy Member in 2017.