Michael Gerard Tyson (born June 1966) is an American former professional boxer who competed from 1985 to 2005. Nicknamed "Iron Mike" in his early career, and later known as "the Baddest Man on the Planet" Tyson is widely regarded as one of the greatest heavyweight boxers of all time, and one of the most intimidating men in boxing history. He reigned as the undisputed world heavyweight champion from 1987 to 1990.