Thiago made his professional debut at Storm Samurai 8 in 2005. He fought Ricardo Petrucio and won the fight via submission in round three. His next three fights came on the same night almost a year after his debut. Thiago competed in the Grand Prix Planaltina, winning all three of his fights and became the tournament winner. Thiago finished all three of the fights by submission. After two more victories, Thiago was signed by Jungle Fights MMA. Thiago won four fights for the promotion before being signed by the Ultimate Fighting Championships. He currently trains with the Constrictor Team, an affiliate of Team Black House; the famed gym of Anderson Silva and the Nogueira brothers.
Thiago never signed a contract before his fight against Koscheck, he was only able to acquire a tryout. Thiago made his UFC debut on February 21, 2009, scoring an upset victory over top contender Josh Koscheck at UFC 95. During the fight, commentator Joe Rogan commented that Thiago's striking looked inferior to Koscheck's. However, Thiago won the fight by KO, with a flush right uppercut and a left hook. The referee stopped the fight before Thiago could pounce on him. Koscheck immediately rose and argued that he was still alert and able to defend himself. Further review of the replay shows Koscheck's eyes roll back as he falls down, giving merit to the stoppage. At the post-fight conference, Dana White confirmed that Thiago had earned Knockout of the Night honors. Thiago had his second fight in the UFC, fighting against former title challenger and Koscheck teammate Jon Fitch at UFC 100. This was Thiago's first fight in the United States and he lost via unanimous decision. Thiago rebounded with a unanimous decision victory over UFC newcomer Jacob Volkmann at UFC 106. In Thiago's fourth outing in the UFC octagon, he was set to have a rematch against Josh Koscheck at UFC 109. However, Koscheck pulled out of the bout after an undisclosed injury and was replaced by AKA teammate Mike Swick. Thiago won via submission in the second round and earned his second UFC fight bonus with the win. Thiago faced Martin Kampmann on June 12, 2010, at UFC 115 where he lost via unanimous decision. Thiago lost his second straight fight via unanimous decision to Diego Sanchez on October 23, 2010 at UFC 121. Though Thiago started the fight off strong by winning the first round, he began to tire and eventually succumbed to the cardio and wrestling skills of Sanchez in the second and third rounds. The bout earned Fight of the Night, awarding both fighters an extra paycheck. In November 2010, Thiago signed a new four-fight deal with the UFC. Thiago was expected to face Johny Hendricks on March 3, 2011, at. However, Thiago was forced out of the bout with an elbow injury. Thiago defeated David Mitchell via unanimous decision on August 27, 2011 at UFC 134, completely dominating Mitchell throughout all three rounds. Thiago was expected to face Mike Pyle on January 14, 2012 at UFC 142. However, Thiago was forced out of the bout with an elbow injury and replaced by Ricardo Funch. Thiago faced Siyar Bahadurzada on April 14, 2012 at. He was knocked out less than a minute into the first round after Siyar landed a right hook to the jaw that followed a left jab as Thiago was moving forward. This marked the first time Thiago had been finished in his career. Thiago next faced Dong Hyun Kim on November 10, 2012 at UFC on Fuel TV 6. He lost the bout via unanimous decision Thiago was expected to face Lance Benoist on May 18, 2013 at UFC on FX 8. However, on April 20, it was announced that Benoist had to pull out of the bout due to an injury. He was replaced by UFC newcomer Michel Prazeres. Thiago won the fight via unanimous decision. Thiago was expected to face Kelvin Gastelum on August 28, 2013 at UFC Fight Night 27. However, Thiago pulled out of the bout citing a knee injury. Thiago faced Brandon Thatch at UFC Fight Night 32 on November 9,2013. He tapped to strikes in the first round after absorbing a knee to the liver. Thiago faced Gasan Umalatov on May 31, 2014 at. He lost the fight via unanimous decision. Despite being 2–6 in his last eight fights inside the octagon, Thiago signed a new four-fight contract with the UFC in June 2014. He was expected to face Mike Rhodes at UFC Fight Night 51 on September 13, 2014. However, Rhodes was forced out of the bout due to injury and was briefly replaced by returning veteran Joe Riggs. Subsequently, Riggs was forced to pull out of the fight after accidentally shooting himself in the leg while cleaning a pistol at his home. Thiago instead faced Sean Spencer. Thiago lost the fight via unanimous decision and was subsequently released by the UFC.
