The 2004 final featured the first red card in MLS Cup history, awarded for a handball which resulted in a penalty kick for Kansas City's second goal.

[2] The 2004 final marked the first time that a stadium had hosted consecutive editions of the MLS Cup,[3] which would be followed by Pizza Hut Park in Frisco, Texas in 2005 and 2006.

[7][10] D.C. United won three MLS Cup titles in the first four seasons of the league's existence, only finishing as runners-up in 1998, and established a dynasty under head coaches Bruce Arena and Thomas Rongen.

[30] D.C. United faced the fourth-seeded New England Revolution, who upset the Columbus Crew in the semifinals, in the Conference Final at RFK Memorial Stadium on November 6, 2004.

The Wizards finished in second place in the Western Conference at the end of the 2003 season,[40] relying on 40-year-old forward Preki as he led the league in scoring and was named the most valuable player.

[45] The team saw their unbeaten streak broken at the end of July before the All-Star Game break, remaining in second place behind the Los Angeles Galaxy in the Western Conference standings.

[47][48] The Wizards also lost starting midfielder Chris Klein to a torn ligament in his knee, while Preki returned only for three matches before being sidelined for an additional ankle surgery.

[49] Kansas City returned from the All-Star break by continuing a four-match winless streak,[50] but finished the season with five wins in the final nine matches to clinch the first seed in the Western Conference.

[51] The team's success was credited to a league-leading defense, conceding one goal per game on average, and strong performances from reserve and replacement players under Gansler.

[55] The Wizards began their playoff campaign in the Western Conference Semifinals against the San Jose Earthquakes, the defending MLS Cup champions.

The team fell 2–0 in the first leg of the series in San Jose, conceding goals to Dwayne De Rosario and Craig Waibel near halftime, but Oshoniyi saved further chances from the Earthquakes.

[60] With a strong defensive performance, Kansas City advanced to their second MLS Cup final on a 2–0 win over Los Angeles; both of the team's goals were scored by Davy Arnaud in the 24th and 69th minutes.

English play-by-play commentary was provided by JP Dellacamera with color analysis by Eric Wynalda, reprising their roles in the previous final.

[66][67][68] The match kicked off at 12:45 p.m. Pacific Time on November 14, 2004, at the Home Depot Center in Carson, California, in front of a crowd of 25,797 spectators—including several hundred traveling D.C. United supporters.

[71] Kansas City took an early lead in the sixth minute after defender José Burciaga Jr. scored on a shot from 30 yards (27 m), following sustained offensive pressure from kickoff.

[69][73] After the referee and an assistant discussed the play, Kansas City were awarded a penalty kick and Kovalenko received the first red card in MLS Cup history for his handball.

[72] Manager Bob Gansler made two substitutions to bring on attacking players, but the team failed to capitalize on chances given to Burciaga in the 81st minute and Matt Taylor in stoppage time.

[77][81] Nowak responded by making several defensive substitutions for D.C., also bringing on Freddy Adu in the 65th minute for Eskandarian, who suffered a leg injury, as the team held onto their lead to win the match 3–2 and clinch an MLS Cup.

[85] 15-year-old substitute Freddy Adu became the youngest member of an American professional championship team in modern sports history, beating a record set by 18-year-old baseball pitcher Art Houtteman with the Detroit Tigers in 1945.

[90] Kansas City tied Deportivo Saprissa in its home leg, but were eliminated by losing 2–1 after extra time the following week in San José, Costa Rica.