[4] He joined the youth academy of Chelsea at under-8 level, following interest from numerous other clubs including Arsenal and Tottenham.
[9] Initially assigned to the club's reserve team, RSCA Futures, Mendel-Idowu scored on his debut in the Challenger Pro League in a 3–2 win against Dender.
[10] On 3 September 2024, Anderlecht confirmed that Mendal-Idowu had left the club to join Premier League side Ipswich Town on a permanent deal.
Mendel-Idowu's maternal grandfather is John Adeleye-Abai, who played for the Nigeria national football team as a winger.
[4] His paternal grandfather, Dr Fola Kayode Mendel-Idowu, was a gifted academic, who specialised in bio-aeronautics and was Africa's first 'flying doctor'.