Brandão made his MMA debut against Michel Bastos, winning via submission. He went 3-1 before fighting against UFC veteran Ronys Torres. He lost the fight by TKO due to punches. He then fought longtime UFC veteran Brian Foster and won via KO in the first round. Following the contest he won 6 and lost four of his next ten fights, with 3 wins by KO, 2 by submission and 1 by decision, before signing with the UFC.
Brandão later became a member of Jackson's MMA in Albuquerque, New Mexico.
The Ultimate Fighter
In 2011, Brandão signed with the UFC to compete on The Ultimate Fighter: Team Bisping vs. Team Miller. In the first episode, Brandão fought Jesse Newell to gain entry into the Ultimate Fighter house. Brandão quickly defeated Newell via first round knockout. He was the number one featherweight pick for Team Bisping.[3]
Brandão proved to be a loose cannon with confrontations with Marcus Brimage and Steven Siler. In the fifth episode it was announced that he would fight Siler on episode six.[4] In this fight Diego charged out of the gate with a flying knee and knocked Siler unconscious 30 seconds into the first round with a left hook. With this win he advanced to the semi-finals to fight former WEC fighter, Bryan Caraway.[5] Brandão defeated Caraway via KO due to a flying knee and follow up punches late in the first round. With the win over Caraway, Brandão moved on to the finale against Dennis Bermudez.[6]
Ultimate Fighting Championship
Brandão officially made his UFC debut on 3 December 2011, at The Ultimate Fighter 14 Finale against Dennis Bermudez to determine the first ever featherweight winner of The Ultimate Fighter 14. After a back-and-forth first round Brandão was knocked down and hit with heavy shots on the ground until he caught Bermudez with an armbar, and quickly forced the tapout. With his performance, Brandão was awarded Fight of the Night andSubmission of the Night honors, giving him a total of $80,000 in bonuses. During the post-fight interview Diego proclaimed of his mother; "The only thing on my mind [is to] buy her [a] house".[7]
Brandão fought Darren Elkins on 26 May 2012, at UFC 146.[8] Brandão lost the fight via unanimous decision.[9]
Brandão fought and defeated Joey Gambino on 13 October 2012, at UFC 153[10] via unanimous decision.[11]
Brandão faced Pablo Garza on 6 April 2013, at UFC on Fuel TV 9.[12] Brandão defeated Garza on UFC on FUEL TV 9 via first round submission with an arm triangle choke.[13]
Brandão faced Dustin Poirier on 28 December 2013, at UFC 168. There was some bad blood between the two that was evident during the staredown at the weigh-in, with Poirier claiming Brandão had threatened to "stab me in the neck."[16] Brandão weighed in at 153 pounds, seven pounds over the accepted 146-pound limit for a featherweight non-title fight. Brandão would continue to cut weight and weighed in an hour later, but could only get down to 151.5 pounds.[17] He was fined 25 percent of his purse, but the bout went on as scheduled.[18] He lost the fight via TKO in the first round.[19]
Brandão was expected to face Will Chope on 23 March 2014, at UFC Fight Night 38.[20] However, Chope was released from UFC when documents were released that showed Chope was discharged from the U.S. Air Force for domestic violence towards his ex-wife.[21]
Brandão was expected to face promotional newcomer Brian Ortega on 31 May 2014, at The Ultimate Fighter Brazil 3 Finale.[22] However, Brandão pulled out of the bout in the days leading up to the event citing an injury. Due to the late nature of the change, officials did not try to find a replacement and Ortega was pulled from the card as well.[23]
Brandão was expected to face Jimy Hettes on 31 January 2015, at UFC 183.[25] However, the fight was canceled right before the event started, as Hettes passed out backstage. He was taken to a local hospital for precautionary reasons.[26] Subsequently, the bout with Hettes was rescheduled for 18 April 2015, at UFC on Fox 15.[27] Brandão won the fight due to a doctor stoppage between the first and second round.
Brandão faced Katsunori Kikuno on 27 September 2015, at UFC Fight Night 75.[28] He dropped his opponent in the bout's opening seconds and followed up with a flurry of punches earning a TKO stoppage.[29] The win also earned him his first Performance of the Night bonus award.[30]
Brandão faced Brian Ortega on 2 January 2016, at UFC 195.[31] After controlling the first two rounds with his striking, Brandão lost the fight via submission in the third round.[32]
On 15 January 2016, it was announced that Brandao had tested positive for marijuana stemming from an in-competition test on 2 January.[33] On 28 April 2016, Brandao was released from the UFC on account of a felony arrest. In ten fights under the promotion, he held a record of 6-4.[34][35]
Fight Nights Global
On 20 October 2016, Brandão signed a contract to fight Russian mixed martial artist Rasul Mirzaev.[36] However, on 3 December, Mirzaev pulled out of the bout for unknown reason. Brandão defeated Murad Machaev on 28 January 2017, at Fight Nights 58.[37]
Absolute Championship Akhmat
Diego faced Salman Zhamaldaev on 26 March 2021 at ACA 120: Oliveira vs. Bibulatov. After tripping Salman in the second round, Diego delivered an illegal soccer kick to the head of Salman while his knee was on the ground. Salman couldn't continue, hence it was announced as an DQ loss for Diego.[38]
Diego faced Alexey Polpudnikov at ACA 134: Bagov vs. Koshkin on December 17, 2021. Brandão lost the bout via TKO in the third round.[40]
Diego faced Bibert Tumenov on February 26, 2022 at ACA 136: Bukuev vs Akopyan. He lost the bout via body shot KO in the second round.[41]
Post ACA career
Following leaving ACA, Diego faced Oleg Lichkovakha at Ural FC 1 on July 1, 2022. He won the bout via TKO in the second round with knees and punches, breaking a six-fight losing streak and winning for the first time since 2019.[42]
He next faced Matt Wagy at AFL: Invincible 2023 on January 20, 2023. He won the bout via KO in the first round with a flying knee.[43][44]
Diego faced Derek Campos at Peak Fighting 29 on June 10, 2023. He won the bout via unanimous decision. [45]
Diego faced Karshyga Dautbek on September 9, 2023 at Alash Pride 89, losing the bout in 36 seconds via TKO stoppage.[46]
^Wheaton, Timothy (26 March 2021). "ACA 120 Results". MMAsucka. Retrieved 26 March 2021.
^"Салман Жамалдаев спорно победил Диего Брандао". AllBoxing.ru - все новости бокса, ММА (MMA), UFC (ЮФС), Bellator, ACA, бои без правил. Видео и фото, прямые трансляции (in Russian). 28 August 2021. Retrieved 13 September 2021.