Obafemi was released by
Watford prior to his 14th birthday in 2014. He took a year out of the game before joining
Leyton Orient in 2015, moving on to
Southampton in 2016.
Southampton Obafemi made his professional debut for Southampton as a
substitute in the 82nd minute of a 1–1 draw with
Tottenham Hotspur on 21 January 2018. Aged 17 years and 199 days, Obafemi became the second youngest player to make a Premier League appearance for Southampton after
Luke Shaw, who was 17 years and 116 days old. He scored his first professional goal with the third goal in a 3–1 victory at
Huddersfield on 22 December 2018; at 18 years and 169 days old, he became Southampton's youngest scorer in the Premier League.
Swansea City On 31 August 2021, Obafemi joined
Swansea City for a fee reported to be between £1.5 and £2 million, signing a three-year contract. On 23 October 2021, Obafemi scored his first goal for Swansea in their 2–1 defeat to
Birmingham City. On the summer deadline day for the 2022 transfer window, Swansea rejected a number of bids from
Burnley for Obafemi with the striker subsequently being left out of the team with concerns from manager
Russell Martin over the striker's attitude.
Burnley On 29 January 2023, Obafemi joined Burnley on loan for the remainder of the season, with a clause to make the transfer permanent at the end of the season. On 1 July 2023, the transfer was made permanent.
Millwall (loan) On 24 January 2024, Obafemi signed for
Millwall on loan until the end of the season.
Plymouth Argyle (loan) On 22 August 2024, Obafemi signed for
Plymouth Argyle on a season long loan.
VFL Bochum (loan) On 1 September 2025, Obafemi signed for
2. Bundesliga club
VFL Bochum on a season long loan, becoming the first Irish player to ever play for the club.
Blackpool (loan) On 21 January 2026, Obafemi joined
Blackpool on loan until the end of the season. ==International career==