Højlund began his career with local side Hørsholm-Usserød IK, a club affiliated with Superliga side Copenhagen, whom he joined alongside his brother Oscar at the age of thirteen.[3] His first taste of senior football came on 9 December 2021, when he was named on the bench for a UEFA Europa Conference League fixture against Slovan Bratislava, though he did not feature as a goal from his brother Rasmus helped Copenhagen to a 2–0 win.[4] He extended his contract with the club on 23 December 2021, alongside his brother Oscar.[3]
On 10 March 2022, Højlund made his professional debut for Copenhagen, coming on as a late substitute for Lukas Lerager in a 4–4 away draw to PSV Eindhoven in the UEFA Europa Conference League.[5] Following the game, manager Jess Thorup said of both Højlund and fellow youth player Roony Bardghji, who had also featured in the game: "We are not afraid to use them, and they showed again that they are ready when it matters."[6]
Højlund scored his first goal for the club in a friendly match against Silkeborg in a 2–1 win on 5 July 2023.[7] He made his Superliga debut on 22 July, coming on as a substitute alongside his brother Oscar as Copenhagen beat Lyngby 2–1.[8]
On 16 July 2024, German club Schalke 04 announced that they had signed Højlund until 30 June 2028.[9]
International career
Højlund has represented Denmark from under-16 to under-19 level.[1]
Style of play
Højlund has been described by Copenhagen's development director Sune Smith-Nielsen as a "complete striker who can play in the two front positions in the centre of the field", with good speed, technique, vision and finishing ability.[3]