Hannibal Mejbri was born on 21 January 2003 in Ivry-sur-Seine, suburban Paris, to Tunisian parents. He came through the prestigious INF Clairefontaine academy before a brief spell at Monaco, which he joined in 2018 for around €1 million. Within a year he had attracted interest from clubs across Europe, and in August 2019 Manchester United secured his signature for a reported fee of around €5 million, potentially rising to €10 million in add-ons.
Mejbri made his senior debut for United in May 2021, coming off the bench in a Premier League win over Wolverhampton Wanderers. A loan spell at Birmingham City in the 2022–23 Championship season proved a key step in his development, where he scored a notable free-kick against West Bromwich Albion that won Birmingham City's Goal of the Season award. He returned to United and scored his first Premier League goal in September 2023 against Brighton.
An energetic, box-to-box midfielder known for his pressing, aggression, and leadership on the pitch, Mejbri joined Burnley permanently in August 2024 on a four-year deal, and the club earned promotion to the Premier League at the end of the 2024–25 season.
On the international stage, Mejbri committed to Tunisia rather than France, making his senior debut in June 2021. He was a standout performer at the 2021 FIFA Arab Cup, where Tunisia finished as runners-up, and represented the country at the 2022 FIFA World Cup in Qatar. He has twice been named African Revelation of the Year at the Africa d'Or awards, in 2021 and 2022.