Born in Dakar, Senegal, El Hadji Malick Diouf began his career with Galaxy Football Academy at the age of 13 and later spent time with Académie Mawade Wade in his homeland.
His first move into European football came at the age of 18 when, following a successful trial, he joined Norwegian top-flight side Tromsø in February 2023.
Diouf made his senior debut the following month in a Norwegian Cup victory over Start and went on to establish himself in the first team during his debut campaign.
He finished 2023 with three goals in 21 appearances in all competitions as Tromsø secured a third-placed Eliteserien finish and qualification for European football.
His performances in Norway earned him a move to Czech giants Slavia Prague in January 2024. Diouf made an immediate impression, scoring on his league debut against Karviná the following month, before making his first appearance in European competition against AC Milan in the Europa League.
The following season proved to be his breakthrough campaign. Operating predominantly as a left wing-back, Diouf scored seven goals and provided three assists in 27 league appearances as Slavia dominated the Czech First League.
They finished 16 points clear at the top of the table, conceding just 18 goals in 35 matches, while Diouf also featured throughout their European campaign.
His form earned him a move to West Ham in July 2025. Diouf made his Premier League debut against Sunderland on the opening weekend of the 2025/26 season and quickly demonstrated his attacking threat from the left.
He registered assists against Chelsea, Nottingham Forest and Crystal Palace during his first five league appearances and ended his maiden Premier League campaign with five assists from 32 outings.
Diouf's rise at club level has been matched by his progress on the international stage. Having represented Senegal at youth level, he made his senior debut in an Africa Cup of Nations qualifier against Burundi in September 2024.
He played the full 90 minutes as Senegal became the first African nation to defeat England with a 3-1 victory at the City Ground in June 2025.
Diouf scored his first senior international goal in an 8-0 friendly victory over Kenya later that year and featured during Senegal's run to the 2025 Africa Cup of Nations final in Morocco.
The defender was subsequently selected for Senegal's squad for the 2026 FIFA World Cup in North America, making his tournament debut against France in June.