After his grandmother died, Williams began to box at the age of nineteen, training with the Daniel M. O'Connell Park Gym in Saint Albans, New York (also known as the New York City Recreations O'Connell Center), walking six miles (9.65 km) to his gym and back each day,[clarification needed] and showing a natural talent and determination.

After the initial successes, he moved to a suburban motel in White Plains, New York, in order to concentrate on training and to stay away from big-city temptations.

Williams eventually fought Mike Tyson (whom he first faced in sparring sessions, August 1, 1983, with a professional record 11–0),[12] in a battle for the undisputed heavyweight championship.

In a post fight in-ring interview, Williams appeared to be uninjured, spoke clearly, and expressed his disappointment that he was not given the opportunity to "show my stuff."

His other notable fights include losses to Larry Holmes, Tim Witherspoon, Tommy Morrison, and Frank Bruno, and wins against Bert Cooper and Trevor Berbick.

Williams worked for Allied-SpectaGuard in New York City at the World Trade Center as a security agent and field supervisor.

Williams would live his everyday life in his boxing apparel, making all appearances while singing the opening line to "Nuthin' But a 'G' Thang."