O'Donkor set the record for the youngest ever Oxford United player at the age of 16 years and 55 days when he made his debut on 8 December 2020 in an EFL Trophy tie against Forest Green Rovers.
[2] On 5 March 2022, O'Donkor joined National League South side Oxford City on an initial one-month loan deal.
[5] He returned to his parent club and made his league debut for Oxford United as a second-half substitute in the last game of the 2021–22 season, a 1–1 draw with Doncaster Rovers, on 30 April 2022.
[9] He scored his first senior goal for the club having come on as a half-time substitute in a League One fixture against Fleetwood Town on 1 November 2022; the game ended in a 1–1 draw.
[11] On 30 August 2024, O'Donkor joined League One club Bristol Rovers on a season-long loan deal.