Damgaard made his professional debut on 13 February 1998, scoring a fifth-round knockout against Antonio Gallegos.
[1] In only his tenth fight, nine months later on 27 November, Damgaard won the vacant European super-lightweight title by stopping Jose Manuel Berdonce in the twelfth and final round.
[2] He would make two defences, against Khalid Rahilou on 16 April 1999 (fourth-round knockout) and Miguel Angel Pena on 1 October 1999 (seventh-round stoppage).
On 28 January 2006, Damgaard travelled abroad for the first time to face established veteran Arturo Gatti in the United States.
A fan-friendly slugfest was the result, at the end of which Damgaard was stopped on his feet in eleven rounds after trailing on all three judges' scorecards.