Gill began his professional boxing career on July 7, 2012, with a four-round points decision victory against Kristian Laight at the Sheffield Arena.
After amassing an undefeated record of 21 wins with 5 knockouts, Gill challenged Ryan Doyle, the Commonwealth featherweight champion, on October 27, 2018, at the Copper Box Arena in London. In the seventh round, Gill dropped Doyle to the canvas with body shots, and although Doyle managed to beat the referee’s count of ten, he was met with a flurry of punches. This prompted the referee, Victor Laughlin, to stop the contest, awarding Gill a seventh-round technical knockout (TKO) victory and making him the new Commonwealth champion.
In early 2019, Gill vacated his Commonwealth title and faced Emmanuel Dominguez for the vacant WBA International featherweight title on March 2, 2019, at the East of England Arena in Peterborough. In a brief fight, Gill knocked down Dominguez twice in the third round and forced the referee to stop the contest by unloading a flurry of punches while trapping Dominguez against the ropes. Gill won the fight via a third-round TKO, securing the regional WBA title.
Gill’s first title defense took place two months later against Mario Enrique Tinoco on May 10 at the Motorpoint Arena in Nottingham. Gill faced adversity in this fight, as he was dropped three times, all due to body punches (once in the third round, again in the fifth, and once more in the seventh). Before the start of the eighth round, Dave Coldwell, Gill’s head trainer, withdrew the champion from the contest to protect him from further damage. Tinoco was declared the winner via eighth-round corner retirement (RTD). Gill later attributed his poor performance to illness, mentioning that he had been dealing with food poisoning on the day of the fight.
Subsequently, Gill was scheduled to face Yesner Talavera on September 19, 2019, in Florence, Italy, and he secured a unanimous decision victory, winning his first fight outside of the United Kingdom with all three judges scoring the fight 60–54 in his favor. He then faced Reece Bellotti on August 1, 2020, and won by unanimous decision, with two judges scoring the fight 97–93 in his favor, while the third judge scored it 96–95 for Gill.
In his next bout, on February 20, 2021, Gill fought Cesar Juarez for the vacant WBA International featherweight title and won by unanimous decision, with scores of 98–92, 98–93, and 96–94.
Gill was originally set to face Karim Guerfi for the European featherweight title on December 11, 2021. However, Guerfi withdrew due to illness, and Alan Castillo replaced him. The fight, which was a non-title bout, ended in a draw by technical decision after three rounds due to a large cut on Gill’s hairline caused by an accidental clash of heads.