[3] In Denmark, he developed a strong partnership in attack with first top goalscorer Kamil Wilczek and since Mikael Uhre and became noted for his pace and pressing abilities.

There, he made his professional debut on 12 August 2012 in a 4–1 league win over Malmö FF, coming on as a late substitute for Niklas Hult.

[6] On 31 July 2014, Hedlund made his first goal in European competition, scoring on a penalty kick in the 89th minute in a 4–1 win over Icelandic club FH in the third qualifying round of the Europa League.

[13] He made the final of the Danish Cup in his first six months in Brøndby, a match against FC Midtjylland which was eventually lost on penalties.

Brøndby head coach Niels Frederiksen explained that other players had impressed more during practice, and that the decision of not including Hedlund was "not a disciplinary punishment".

[16] He would, however, finish the season strong as a key part of the Brøndby offense alongside top goalscorer Mikael Uhre and Jesper Lindstrøm as the club won its first Danish Superliga in 16 years.

[17][18] Hedlund contributed with nine goals and nine assists in 33 appearances in the club's title-winning season, and was voted Superliga Player of the Month for May 2021 for his performances.

[20][21] He made his return debut for the club on 3 September, replacing André Boman at half-time in a 1–0 league loss away against IFK Värnamo.

[26] Renowned for his pace with and without the ball at his feet, Hedlund has described himself as a "hard worker",[27] and was praised for evolving into a true team-player during his time at Brøndby by head coach Niels Frederiksen.