Grant was born in Bishop Auckland, County Durham, England. He started kickboxing training when he was 14 and picked up grappling on later date where he had his first amateur fight at the age of 15. Along with training MMA, Grant also played football and rugby during his teenage years. He decided to take it seriously when he was 21 where he decided to be a professional fighter after he won a fight just to prove to his friends he had trained in MMA. He was cast in the TUF 18, UFC TV series program aired on BT Sport in the UK in 2013. He made it to the final for TUF 18 and despite the loss to Chris Holdsworth, he was signed by UFC.
Grant was selected as one of the cast members for , UFC The Ultimate Fighter TV series, under Team Ronda Rousey in September 2013. In the elimination round, Grant submitted Louis Fisette in round 2. Grant next faced Anthony Gutierrez. Gutierrez did not make weight and was expelled from the show and Grant advanced to the Final facing Chris Holdsworth in.
Grant made his UFC debut on November 30, 2013 at in Las Vegas, United States against Chris Holdsworth for the bantamweight UFC The Ultimate Fighter 18 title. He lost by rear-naked choke in round two. Grant was expected to face Roland Delorme at and it was cancelled after the weigh ins the day before the event due to Grant suffering a torn meniscus. He voiced his disappointment for not being able to make the fight in front of his home crowd in an interview: After a 25-month hiatus from competing, after his UFC debut, due to separate injuries to his knees, ankle and back, on February 27, 2016, Grant was took up Marion Vera at. He won the fight via unanimous decision with a score of "30–26", across the board. On October 8, 2016, Grant faced Damian Stasiak at UFC 204. He was submitted via an armbar and lost the fight. Grant and Stasiak felt the cracked of Grant's arm twice during the submission, and Grant said in his post-fight interview: After an 18-month hiatus, Grant was scheduled to meet Manny Bermudez on May 27, 2018 at UFC Fight Night 130. However, Grant pulled out of the fight after being diagnosed with a staph infection, and the bout was scrapped. The pairing was left intact and took place on July 22, 2018 at UFC Fight Night 134. He lost the fight via a triangle choke. Grant faced Grigory Popov on November 9, 2019 at UFC on ESPN+ 21. He won the fight via a split decision. Grant was expected to face Louis Smolka on March 28, 2020 at. Due to the COVID-19 pandemic, the event was eventually postponed. Grant faced Martin Day on July 11, 2020 at UFC 251. He won the fight via knockout in the third round. This win earned him the Performance of the Night award.
