Oscar Højlund

Højlund began his career with local side Hørsholm-Usserød, a club affiliated with Superliga side Copenhagen, whom he joined alongside his brother Emil at the age of thirteen. The pair extended their contracts with the club on 23 December 2021. His first taste of senior football came when he was named on the bench for a Superliga game against Viborg on 19 March 2023, though he did not feature. Two months later, following a number of injuries and suspensions to first team members, Højlund was again called up to the senior squad ahead of the Superliga fixture against AGF on 21 May, though he remained on the bench in this game. Højlund made his unofficial debut for the club in a friendly match against Silkeborg in a 2–1 win on 5 July 2023. He made his Superliga debut on 22 July, coming on as a substitute alongside his brother Emil as Copenhagen beat Lyngby 2–1. The following month he made his European bow for Copenhagen, coming on as a second-half substitute for Elias Achouri in a 6–3 win against Icelandic opposition Breiðablik in qualification for the UEFA Champions League on 2 August.

Eintracht Frankfurt

On 10 July 2024, it was announced that Højlund had signed a 5-year contract with German club Eintracht Frankfurt until June 2029.

Højlund has represented Denmark at under-17 and under-18 level.

Højlund has been described by Copenhagen's development director Sune Smith-Nielsen as an "energetic and dynamic central midfielder who can run from end to end", with good technique, vision and reading of the game.

Højlund was born to former Danish footballer Anders Højlund, who played in the Danish Superliga with B.93. He is the twin brother of Schalke 04 footballer Emil Højlund, and the younger brother of Danish international and Napoli footballer Rasmus Højlund.