Amateur career

Lacy had 210 fights as an amateur, winning the 1999 National PAL amateur champion at 165 pounds, the 1998 U.S. National amateur champion at 165 pounds, and the 1998 National PAL amateur champion at 165 pounds. Lacy fought at the 1996 Eastern Olympic Trials, stopping Kenneth Head in the first round. In the quarter finals, Lacy defeated Rubin Williams. In the semi finals, Lacy lost to darnell Wilson and finished third.

In the 1997 National Golden gloves, Lacy again defeated Rubin Williams, but lost against Randy Griffin in the semi finals and finished in third place. In the quarter finals of the 2000 Olympic team trials, Lacy won a decision over Brad Austin. In the semi finals, Lacy won a decision over Jerson Ravelo. During the finals, Lacey won a 26-10 decision over Randy Griffin.

Professional career

Rise to stardom

Lacy made his professional debut against Jerald Lowe on February 2, 2001, knocking him out in the first round. He won his next eight fights by way of knockout and won the WBC Continental Americas super middleweight title against Anwar Oshana, by way of technical knockout in round two.

On July 15, 2003, he won the USBA and NABA super middleweight titles after beating Richard Grant by unanimous decision. He defended all three of his belts against Donnell Wiggins by TKO 8. He later fought Syd Vanderpool for the vacant IBF super middleweight title on October 2, 2004, winning by TKO in 8 rounds. He defended it against Omar Sheika, Rubin Williams, former champion Robin Reid, and Scott Pemberton.

Loss to Joe Calzaghe

On March 5, 2006, at the MEN Arena in Manchester, England, Lacy lost his title to Joe Calzaghe. Despite being a favorite going into the fight, Lacy lost by a unanimous points decision and was knocked down in the twelfth round. Lacy, who had promised a knockout victory pre fight, was the betting favorite largely due to his age and the nature of his recent title defenses. He started the fight very aggressively but was immediately troubled by Calzaghe's toughness and handspeed. Lacy was hit with a plethora of hurtful punches as Calzaghe managed to consistently land a staggeringly high volume of shots. Lacy continued to try and feint his way in quickly to land his famous left hook but Calzaghe was able to evade or ride the shot. As the match wore on Lacy became increasingly disheartened, and his face a bloody mess. The fight became more and more punishing throughout the middle, and into the later rounds with many expecting the referee to halt the action and save Lacy from such a horrendous beating. To the criticism of onlookers, Lacy's corner continued with the fight in the belief that he could still turn the fight around with one punch. In the end the result was extremely one sided with final scores of 119-105, 119-107 and 119-107. A point deducted from Calzaghe in the 11th round was all that prevented Lacy from losing every round on every car. Many observers have been vocal in their belief that the nature of the loss to Calzaghe meant that Lacy was from then on a shell of his former self.

After Calzaghe

Lacy fought a rematch with Vitali Tsypko on December 2, 2006, in Tampa, Florida, on the same card as Winky Wright's fight against Ike Quartey. This was the second time he had fought Tsypko, the first fight in 2004 which ended in a majority decision. Lacy won the fight by scores of 96-94, 96-94, 95-95. After the bout, it was revealed that Lacy had torn his rotator cuff and was injured throughout most of the fight. Lacy had surgery on the injury and did not fight for a year after the bout.