Aged 15 years and 86 days, he made his professional debut in a Football League Trophy match for Bury on 30 August 2016, coming on as an 85th-minute substitute in a 4–1 win over to Morecambe becoming the youngest player in the club's history.[3]
In October 2016, Obi moved to Liverpool for a six figure fee plus performance based add ons.[4] Despite the move, he did not appear on Liverpool's Under 18 squad lists for the 2016–17 or 2017–18 seasons.
Between September and December 2017 he appeared a number of times for Wigan Athletic's Under 18 squad, scoring in two matches.[5] At the start of the 2018–19 season he was again featuring for Wigan.[6]
In November 2018, he signed his first professional contract with Wigan Athletic.[5]