DeRoux signed a developmental contract with D.C. United on 15 September 2005, and subsequently played in 10 games for the team, but following the conclusion of the 2007 season, United did not exercise DeRoux's contract option.

Although he was invited to rejoin United during the 2008 pre-season training camp to attempt to re-earn a roster spot,[1] he was not offered a contract with the team.

DeRoux spent the 2008 season with Minnesota Thunder in the USL First Division, playing 29 games and scoring 1 goal, before moving to Montreal Impact in 2009.

[2] During the 2009 USL season DeRoux contributed by helping the Impact clinch a playoff spot under new head coach Marc Dos Santos.

He helped the Impact reach the finals where Montreal would face the Vancouver Whitecaps FC, this marking the first time in USL history where the final match would consist of two Canadian clubs.