Ipswich Town Born in
Paris, El Mizouni came through the academy at Ipswich. He signed his first professional contract on 20 December 2018, signing a two-and-a-half-year contract at Ipswich until 2021, with the option of an additional year extension. He made his professional debut for the club on 12 March 2019, in a 1–1 draw against
Bristol City at
Ashton Gate. El Mizouni made four appearances in his debut season at
Portman Road, having progressed through the club's under-18 and under-23 sides into the first team over the course of the 2018–19 season. His progress earned him his first call up to the senior
Tunisia squad in June 2019, making him the first player in the club's history to be capped for Tunisia at senior level. He scored his first professional goal on 4 December 2019, scoring the opening goal in a 1–1 draw with
Peterborough United at the
London Road Stadium in an
EFL Trophy second round tie, with Ipswich going on to win the match 6–5 on penalties.
Cambridge United (loans) On 23 January 2020, El Mizouni joined
League Two club
Cambridge United on loan for the remainder of the 2019–20 season. He made his debut for the club on 25 January, appearing as a second-half substitute in a 1–1 draw with
Morecambe. He scored his first goal on 11 February, netting a 20-yard free-kick in a 0–2 away win over
Scunthorpe United. His loan spell at Cambridge was ended on 2 March after suffering medial ligament damage to his knee during a 2–1 loss to
Carlisle United on 29 February, ruling him out of action for the rest of the season. He made seven appearances during his loan spell at the club, scoring once. On 22 September 2020, El Mizouni rejoined Cambridge United on a season-long loan for the 2020–21 season. He made his first appearance of the 2020–21 season as a second-half substitute in a 0–0 draw with
Tranmere Rovers on 26 September. He did not feature as regularly during his second loan with Cambridge, only making three league starts between September and December. On 3 January, Ipswich took the option to recall El Mizouni from his loan spell. He made 15 appearances in all competitions during his second loan at Cambridge.
Grimsby Town (loan) On 29 January 2021, El Mizouni joined
Grimsby Town on loan for the rest of the 2020–21 season. He made his debut for Grimsby the following day in a match against
Stevenage. In March, El Mizouni suffered a hamstring injury, potentially ruling him out for the remainder of the season.
Return to Ipswich On 10 May 2021, Ipswich announced that they had taken up the option to extend El Mizouni's contract by an additional year, keeping him under contract until 2022. On 9 November 2021, El Mizouni signed a new two-and-a-half-year contract with Ipswich, keeping him at the club until 2024, with the option of an additional one-year extension. The following match after signing his new contract, he scored a stunning winner from 30 yards out in a 2–1 win against
Oldham Athletic in an
FA Cup first round replay, with the goal winning him the Goal of the Round award and a place in the Team of the Round for the FA Cup first round.
Leyton Orient (loan) On 12 August 2022, El Mizouni joined
League Two Leyton Orient on loan for the 2022–23 season. Leyton Orient won League Two. On 5 July 2023, it was announced that he would be loaned to Orient again for the whole of 2023–24, this time in
League One. On 3 June 2024, Ipswich said it had extended the player's contract by another 12 months.
Oxford United On 9 July 2024, El Mizouni signed for
EFL Championship side
Oxford United.
Return to Leyton Orient On 4 July 2025, El Mizouni returned to League One side Leyton Orient on a permanent three-year deal for an undisclosed club record fee. ==International career==