Lambert made his debut in the UFC at UFC 58: USA vs. Canada as a late replacement for The Ultimate Fighter 2 cast member Seth Petruzelli, who suffered a concussion while training and had to withdraw from the bout. Lambert's debut was successful, submitting his opponent, Rob MacDonald, early in the first round. Lambert fought again at UFC 59, defeating Terry Martin by technical knockout at 2:37 of round two. This was a preliminary fight that did not air on the pay-per-view broadcast. His next fight, against Branden Lee Hinkle at Ultimate Fight Night 5, marked Lambert's third consecutive UFC victory. Despite this initial win streak, he was not seen on a live UFC pay-per-view broadcast until UFC 63, where he lost to Rashad Evans by knockout in the second round. At UFC 68, Lambert defeated veteran and former title challenger Renato "Babalu" Sobral in a stunning upset by second-round knockout. Lambert was scheduled to fight Wilson Gouveia at UFC 76: Knockout, but the bout was rescheduled to UFC 80: Rapid Fire after Gouveia suffered an injury in training. Lambert was knocked out by Gouveia by a left hook which, ironically, was identitical to the hook used by Lambert in his last fight to finish Renato Sobral. Lambert then lost at UFC 85: Bedlam via TKO at the hands of Luiz Cané at 2:07 of the first round. Lambert moved down to the Middleweight division, and fought Canadian Jason MacDonald at UFC 88: Breakthrough in Atlanta, Georgia, on September 6, 2008. He lost by rear-naked choke in the second round. After the loss to MacDonald that marked his third straight defeat, the UFC has released Lambert from his contract, saying that he "needed to get more wins".
Post-UFC
In his first bout after his release from the UFC, Lambert lost a unanimous decision to Vladimir Matyushenko at Call to Arms I on May 16, 2009. Lambert then faced Matt Horwich, at AMMA 1 - First Blood, on October 24, 2009. He lost the fight via split decision, posting a record of 0-2 since leaving the UFC. He then fought twice in the C3 Fights promotion, defeating Dominic Brown and Wayne Cole by TKO and rear-naked choke submission respectively. The two wins in the promotion marked his first win streak since 2006.
Lambert signed with Bellator MMA and made his debut against former UFC veteran Hector Ramirez at Bellator 85. Lambert won the bout via armbar submission. He then faced Tom DeBlass at Bellator 108 on November 15, 2013. Lambert lost the fight via first round KO.
Championships and accomplishments
Icon Sport
*SuperBrawl 24: Return of the Heavyweights Tournament Semifinals
