The Ultimate Fighter Barnatt had a record of 5-0 before being selected as a member of
The Ultimate Fighter: Team Jones vs. Team Sonnen In January 2013. Barnatt defeated Nicholas Kohring by decision to qualify the TUF house. During the choosing of teams, he was the first pick of
Chael Sonnen of Team Sonnen and the first pick overall. Barnatt defeated Gilbert Smith, Jr. in the preliminary round via second-round knockout, but was eliminated in the quarter-finals by
Dylan Andrews.
Ultimate Fighting Championship Barnatt made his UFC debut against fellow Ultimate Fighter castmate Collin Hart on 13 April 2013 at
The Ultimate Fighter 17 Finale and won the fight via unanimous decision. Barnatt faced
Andrew Craig on 26 October 2013 at
UFC Fight Night: Machida vs. Munoz and won the fight via submission in the second round. The fight also earned Barnatt his first
Fight of the Night bonus award. Barnatt faced promotional newcomer
Mats Nilsson at
UFC Fight Night 37 and won the fight via TKO due to strikes in the first round. Barnatt faced
Sean Strickland on 31 May 2014 at
UFC Fight Night 41 and lost the fight by a split decision. 11 out of 11 media outlets scored the bout for Barnatt. Barnatt faced
Roger Narvaez on 22 November 2014 at
UFC Fight Night 57 and lost the fight via split decision. Barnatt was expected to face
Clint Hester on 4 April 2015 at
UFC Fight Night 63. However, Hester pulled out of the fight in early March due to a broken foot. Subsequently, Barnatt was pulled from the card entirely in favor of a matchup with
Mark Muñoz on 16 May 2015 at
UFC Fight Night 66. He lost the fight by unanimous decision and was subsequently released from the promotion.
Post-UFC; Independent promotions Barnatt fought for Italian promotion Venator FC against Mattia Schiavolin on 12 December 2015 at Venator FC 2 in a fight for the promotions middleweight championship. He took the title by winning the fight by submission due to a rear-naked choke in the fourth round. He was expected to face Rafael Silva on 20 February 2016 at British Challenge MMA 14. However his opponent was later changes to be Charles Andrade. He won the fight by knockout after dropping his opponent to the canvas with a right hand, 11 seconds into round 3. Barnatt was expected to defend his Venator middleweight championship against fellow UFC veteran
Jason Miller on 21 May 2016 at Venator FC 3. However, Miller missed weight by an amount of 24 lbs, as a result of this Miller was removed from the matchup against Barnatt and replaced by Stefan Croitoru. Barnatt won the fight, and defended the title, by TKO in round 2. He fought Cristian Mitrea, in a light heavyweight match-up, on 19 December 2016 at
RXF 25: All Stars in Romania. After stunning his opponent by punches and knees up against the fence, Barnatt landed a head kick to earn the knockout victory, 3 minutes into the first round.
Absolute Championship Berkut Barnatt faced
Mamed Khalidov on 11 March 2017 at
ACB 53. He lost the fight via knockout in the first round. Luke fought
Scott Askham on 23 September 2017 in the main event at
ACB 70. He lost the fight by split decision and earned fight of the night bonus. He went 2-3 overall before the promotion changed names from ACB to ACA- Absolute Championship Akhmat and went 1-4 in his last 5 and retired in 2020. ==Championships and accomplishments==