The MLS Cup is the league's annual championship game and the conclusion of the MLS Cup Playoffs. The winner of the Eastern Conference Final faces the winner of the Western Conference Final in this game, which takes place in December. The league champion is determined by who wins the MLS Cup.

Every other major North American sports league employs a playoff tournament after the regular season to choose its yearly league champion. This structure contrasts with other soccer leagues throughout the world, which award the Supporters' Shield to the team with the highest points at the end of the season.

A team from the United States that wins the MLS Cup is given one of the country's four spots in the CONCACAF Champions League the following season. The three MLS Canadian teams can only qualify for the Champions League through the Canadian Championship; if one of them wins the MLS Cup, the Champions League slot is given to the highest-placed U.S.-based team in the overall regular-season table who did not previously qualify.

MLS Cup year by year winners

The winner of the MLS Cup, the last match of the MLS Cup Playoffs, becomes the league champion for that season. The league hosts a postseason event at the end of the regular season in a structure similar to that of other North American professional sports leagues.

The tournament is accessible to the Eastern and Western Conference's top seven teams. On October 20, 1996, the inaugural MLS Cup final was held, when DC United beat the Los Angeles Galaxy to lift the trophy. With five cup triumphs to date, the Galaxy hold the record for most championships.

The New England Revolution hold the record for most championships lost, having lost five times in their existence. On three times, the tournament has been won by the same squad for two or more years in a row.

Year Winner Country
1996 DC United USA
1997 DC United USA
1998 Chicago Fire USA
1999 DC United USA
2000 Kansas City Wizards/Sporting Kansas City USA
2001 San Jose Earthquakes USA
2002 Los Angeles Galaxy USA
2003 San Jose Earthquakes USA
2004 DC United USA
2005 Los Angeles Galaxy USA
2006 Houston Dynamo USA
2007 Houston Dynamo USA
2008 Columbus Crew USA
2009 Real Salt Lake USA
2010 Colorado Rapids USA
2011 Los Angeles Galaxy USA
2012 Los Angeles Galaxy USA
2013 Sporting Kansas City USA
2014 Los Angeles Galaxy USA
2015 Portland Timbers USA
2016 Seattle Sounders USA
2017 Toronto FC Canada
2018 Atlanta United USA
2019 Seattle Sounders USA
2020 Columbus Crew USA
2021 New York City FC  USA