James Toney had his first professional fight on October 26, 1988, beating Stephen Lee by a technical knockout in the second round. A draw with Sanderline Willliams was the first blemish on Toney's record, although he beat Williams by unanimous decision three months later.

A notable win by Toney in his early career was over fellow middleweight prospect Merqui Sosa in 1991.

IBF Middleweight champion Michael Nunn defended his title against Toney on May 10, 1991, in Nunn's hometown of Davenport, Iowa. Nunn was leading on the scorecards when Toney knocked him out in the eleventh round.

Toney defended his title against Reggie Johnson one month later, and then defeated Francesco Dell'Aquila in October of 1991. Former junior middleweight and middleweight champion and Mike McCallum held Toney to a draw in December 1991.

His next fight, against David Tiberi of Delaware, resulted in a controversial win for Toney. Many observers saw Tiberi the victor, and Delaware Senator William Roth held a Senate hearing on boxing as a result of this decision.

Two more defenses of Toney's Middlweight title followed, including a decision over Mike McCallum in a rematch.

Toney moved up to the super middlweight division and won the IBF Super Middleweight title from Iran Barkley in an entertaining slugest on February 13, 1993. He made three defenses (including one of former IBF Light Heavyweight champion Charles Williams) before meeting IBF Middleweight champion Roy Jones Jr. on November 18, 1994. Roy Jones easily beat Toney, even knocking him down in the third round. Toney claimed that making the super middleweight limit had been too draining and that he would campaign as a light heavyweight.

Toney entered a period of years when he seemed to lose focus on boxing. His performances were uneven and his weight steadily increased. His fight after losing his title to Roy Jones saw him lose to Montel Griffin at light heavyweight in February of 1995. After winning a series of fights at light heavyweight, cruiserweight, and even heavyweight, he again faced Montell Griffin in December, 1996, and once again lost a close decision. He beat old foe Mike McCallum in February, 1997, but then lost to journeyman Drake Thadzi in his next fight.

He continued to fight at cruiserweight and light heavyweight, beating a variety of undistinguished opponents.

In August, 2002, Toney beat Jason Robinson in an IBF Cruiserweight title elimination fight. This set up a fight between Toney and IBF Cruiserweight champion Vasily Jirov. After a postponement, the fight came off on April 26, 2003, and Toney won a unanimous decision from Jirov.

Immediately afterward, Toney moved up to heavyweight.

Even when Toney was a middleweight, he insisted that he would one day be the heavyweight champion of the world. His good handspeed, slick defense, and exceptional counterpunching have enabled him to defeat physically larger (but technically less-skilled) opponents. His October 4, 2003 victory over aging former World Heavyweight Champion Evander Holyfield was Toney's entry into the heavyweight division.

On April 30, 2005 he defeated John Ruiz by unanimous-decision in a 12-round match for the World Boxing Association (WBA) world Heavyweight Championship. However, as of May 18, 2005, it was [1] reported that Toney failed his post-fight drug test, testing positive for anabolic steroids. This led to the New York Athletic Commission changing the bout's official outcome to a "no-contest", deducting the win from Toney's career record, and banning him from boxing for 90 days. The WBA ordered that Ruiz be "reinstated" as its champion, and that Toney is ineligible for another WBA Heavyweight Title shot for the next two years (potentially a lifetime ban, given Toney's advancing age).

In July 2005, the Los Angeles Times reported that Toney's suspension (testing positive for nandrolone) would expire on July 30. Throughout his suspension, Toney has made numerous public appearances — including guest-commentating on boxing telecasts — and emphatically stated his desire to fight again for a heavyweight championship. Toney also defends that the steroids were given to him by a doctor to treat an injured arm that occurred during his victory over Rydell Booker in his previous fight. Ironically, Toney's name has been placed above Ruiz's in some widely-circulated, post-suspension media rankings of heavyweight boxers (like ESPN.com's; [2]). This may be as much due to Ruiz's low popularity with boxing fans as Toney's colorful persona, highly respected reputation, and career staying power. Toney recently won a unanimous decision victory over Dominic Guinn, in which he dominated. Toney's most recent fight - against Hasim Rahman on March 18th, 2006 — resulted in a 12 round draw. Toney's next outing will be on Sept 2, 2006 against Sam Peter.