The Seattle Sounders FC debuted as the league's 15th club and were the second team in history to qualify for the MLS Cup Playoffs in their inaugural season.

The club set a league record for attendance and averaged 30,943 per regular season match at Qwest Field.

Real Salt Lake won their first MLS Cup by defeating the Los Angeles Galaxy in a penalty shootout.

The team with the most points in the regular season was awarded the MLS Supporters' Shield and qualified for the CONCACAF Champions League.

Additionally, the winner of MLS Cup, and the runner-up, also qualified for the CONCACAF Champions League.

Qualification for the SuperLiga was awarded to the top four overall finishers not already qualified for the CONCACAF Champions League.