[3] He played all Midtjylland's matches during the 2003–04 Danish Superliga season and was rewarded with a new contract in November 2004, keeping him at the club until 2007.

[5] On 19 June 2007, Bak signed a four-year contract with the Dutch Eredivisie club SC Heerenveen.

[9] On 10 February 2010 he was fined €1,000 by the Royal Dutch Football Association (KNVB) prosecutor for allegations against referee Kevin Blom.

He replaced Thomas Kahlenberg in the extra time of the second half, in a match which Denmark won 3–0.

[15][16] On 20 November 2006, he was called up for the Denmark League XI, playing unofficial games against the United States, El Salvador and Honduras in January 2007, by national team manager Morten Olsen.

[20] In June 2022, Bak changed position in Midtjylland to assistant Sporting Director.