Alexis Saelemaekers was born on 27 June 1999 in Berchem-Sainte-Agathe, Belgium, and came through R.S.C. Anderlecht's youth system. He made his senior debut in February 2018 and impressed enough across 57 league appearances for Anderlecht to attract Italian interest.
In January 2020 AC Milan signed him on loan and made the deal permanent that July. He won the 2021-22 Serie A title with the Rossoneri, but seeking more minutes he was loaned to Bologna for 2023-24, where he was a key piece of Thiago Motta's high-flying side. After a planned permanent move broke down he returned to Milan and was loaned again — this time to Roma — for the 2024-25 season, where he posted a career-best seven goals across all competitions.
For 2025-26 he has returned to Milan, wearing number 56, and is competing for a starting spot on either flank under the new regime.
He earned his Belgium debut in October 2020 against Ivory Coast and has accumulated more than 20 caps, scoring twice during 2022 World Cup qualifying. He featured in Belgium's Euro 2024 squad.
A 1.80 m attacker primarily used as a right winger, Saelemaekers can also play as a left winger or a wing-back/full-back on either flank — a versatile, hard-working profile that has kept him in elite squads since his teenage years despite never being a guaranteed starter.