[3] On 14 April 2019, Klysner made his professional debut for Randers, in a Danish Superliga match against Hobro IK.
Randers confirmed on 11 June 2019, that Klysner had signed a professional four-year contract with the club and was permanently promoted to the first team squad.
[9] On 1 September 2023, Klysner joined Norwegian Eliteserien side Aalesund on a loan deal for the rest of 2023, with a purchase option included.
[10] Klysner had barely landed in Norway before he got injured, and therefore didn't get more than three minutes of playing time in Aalesund before returning to OB at the turn of the year.
[11] On 25 January 2024, Klysner joined Danish 1st Division leaders Sønderjyske on a three-year contract.