He made his MLS debut on April 8, 2007, starting in central defense against the Houston Dynamo in a 0–0 tie.

In February 2008, Harden announced his retirement after only one season as a professional soccer player, deciding instead to work for a charitable organization and to finish college at the University of Washington[1] Despite retiring in 2008, his rights were transferred to Colorado Rapids on January 13, 2009.

[2] Harden was traded on February 10, 2010, to Toronto FC for a third-round draft pick in the 2011 MLS SuperDraft.

Harden suffered a deep gash to his shin that required 22 stitches after a collision while scoring from a corner on April 28, 2010, against rivals Montreal Impact in the first game of the 2010 Canadian Championship.

[5] He chose to participate in the 2012 MLS Re-Entry Draft and was selected in stage two by San Jose Earthquakes.