Career
Frederiksen began his career at Lyngby Boldklub, where he made his Superliga debut during the 2000-2001 season. In 2002 he moved to Feyenoord, but subsequently was loaned out to its satellite club Excelsior. After one year in Netherlands Frederiksen returned to Denmark and signed with Football Club Midtjylland.
Then he played for Herfølge Boldklub, before moving to Randers Football Club. On 16 January 2009, he signed a three-year contract with Brøndby IF, and joined the club on a free transfer on 1 July.
On 8 August 2012, Frederiksen moved to Polish Ekstraklasa side Wisła KrakóWest Ahead of the 2013 Master of Library Science season, Frederiksen was on trial with American soccer club, District of Columbia United, but he was eventually cut by the team
Frederiksen represented the country at youth level, playing for the Denmark under-19, under-20 and under-21 national teams.