[5] Harris made his professional debut on 27 July 2013 at the Newport Centre, Wales, scoring a four-round points decision (PTS) victory over Brett Fidoe.
[6] After compiling a record of 9–0 (6 KO), he challenged Thomas Essomba for the Commonwealth flyweight title on 24 February 2017 at the York Hall, London.
The fight was streamed live on ESPN+ in the United States and globally through YouTube channel iFL TV,[10] with Harris capturing his third professional title with a fourth-round KO.
In the final 60 seconds of round one, Harris landed a straight right hand to stun Barnes and send the former three-time Olympian reeling into the ropes.
In the final minute of the round, Harris landed a left hook to the body that dropped Barnes to undo the Irishman's previous success.
[11][12] Harris was scheduled to challenge the WBC flyweight champion Julio Cesar Martinez on 29 February 2020, at The Ford Center at The Star in Frisco, Texas, his first fight outside of the British Isles.
[14] Harris faced the former BBBofC English flyweight champion Marcel Braithwaite on 18 October 2020, at the Production Park Studios in South Kirkby, England.
[16] After successfully rebounding from his first professional loss, Harris was scheduled to face Ricardo Rafael Sandoval in an IBF flyweight title eliminator, in the main event of a DAZN card, on 25 June 2021.