At the time Cooper had intended to attend Southern Methodist University, but decided to forgo playing college soccer in order to pursue his professional career.Cooper made his first MLS start the following week against Real Salt Lake on April 8, 2006, scoring the team's first goal in a 2–1 victory.On January 13, 2011, TSV 1860 Munich announced that Cooper would not fulfil his contract which had been set to run until June 2012 and would be joining Portland Timbers on a free transfer.[11] On January 12, 2012, Cooper was traded to the New York Red Bulls for a first-round 2013 MLS SuperDraft pick and an undisclosed amount of allocation money.[16] In his first season with the club Cooper helped Seattle in capturing the 2014 Lamar Hunt U.S. Open Cup scoring six goals in four games, including a two-goal, two-assist effort in the semifinals against Chicago on August 13.After the retirement of Brian McBride, Cooper was considered to be a potential long-term solution at striker for the national team.He then appeared in a game against Guatemala, which was played in his MLS club's home stadium, Pizza Hut Park, as a second half sub.On July 18, 2009, Cooper took a boot to the chest from Roman Torres of Panama, resulting in a penalty kick which he took to put the U.S. through to the semifinal round of the CONCACAF Gold Cup.[24] Five days later, Cooper scored near the end of the match against Honduras to give the U.S. a 2–0 lead and to put them safely into the final of the 2009 CONCACAF Gold Cup.