[17][18] In a press conference at the Columbia Center on November 13, 2007, it announced that Seattle had been awarded an MLS expansion team that would be owned by Hanauer, Roth, Allen, and TV personality Drew Carey.

[26] Seattle Sounders FC entered MLS as the league's 15th team and played its first home match on March 19, 2009, in front of a sold-out crowd of 32,523, defeating the New York Red Bulls 3–0.

[42] In the U.S. Open Cup, Seattle won matches at Portland and at home against the Los Angeles Galaxy and Chivas USA before reaching the final, which they hosted at Qwest Field against the Columbus Crew.

[51] On October 4, 2011, Seattle won its third consecutive U.S. Open Cup, becoming the first club to do so in 42 years, as they defeated the Chicago Fire 2–0 in front of another tournament record crowd of 35,615 at CenturyLink Field.

[60] Seattle reached the U.S. Open Cup Final for the fourth consecutive year, becoming the first team to do so since 1937,[61] but lost to Sporting Kansas City in a penalty shootout after a 1–1 draw.

[67] During the 2013 preseason, the Sounders signed their first homegrown player, right back DeAndre Yedlin,[68] veteran defender Djimi Traoré,[69] and forward Obafemi Martins, who paid his release clause to his Spanish club.

[91] Entering the playoffs as the top seed, Seattle defeated FC Dallas on the away goals rule and advanced to the Western Conference Championship to face the LA Galaxy once again.

[100] The playoff run would end in the next round, the Western Conference semifinals against FC Dallas, during a penalty shootout after both teams were tied on aggregate score after extra time in Frisco, Texas.

Following a 3–0 loss on July 24 to Sporting Kansas City, in which the Sounders had only one shot,[108] Schmid left the club on mutual terms and was replaced by long-time assistant coach Brian Schmetzer.

[124][125][126] In the playoffs, the Sounders beat the Vancouver Whitecaps and Houston Dynamo to win the Western Conference and return to the MLS Cup, once again facing Toronto at BMO Field.

The club signed a new Designated Player, Peruvian forward Raúl Ruidíaz, that month and began a long unbeaten streak that resulted in a playoff position in late August.

[138] Despite the loss of these two players, in addition to the suspension of Román Torres for ten matches for testing positive for a performance-enhancing substance in August,[139] the Sounders finished 2nd in the Western Conference and 4th in the overall league table.

[146] The Sounders played two regular season matches at home before MLS suspended all activities on March 12, 2020, due to the worsening COVID-19 pandemic, which had been affecting the Seattle area for several weeks.

[154] Minnesota took a 2–0 lead in the second half, but Seattle responded with three goals in the final 18 minutes to complete a comeback victory and secure a fourth MLS Cup appearance in five years.

[155] The Sounders faced the Columbus Crew in the 2020 MLS Cup final and lost 3–0 in front of 1,500 spectators at Mapfre Stadium on December 12—the latest calendar date to host a league match.

[156] Seattle opened the 2021 season with a 13-match unbeaten streak, setting a new MLS record in the process, despite missing Nicolas Lodeiro, Jordan Morris, Stefan Frei, and Raul Ruidiaz to long-term injuries.

[168] The club resumed league play, where they had fallen to 13th place in the Western Conference, and used rotated lineups to balance a congested schedule; by early July, they had improved to fourth in the West.

It used colors and elements from previous Sounders logos around a simplified version of the shield, which contained the Space Needle and omitted all text except for 1974, the year of the club's founding.

[191][192] A set of secondary and tertiary logos were also added, including an orca, the "SFC" wordmark, and a carnation—which are traditionally given by Sounders players to fans at the end of the final home match of the season.

[210][211] The choice of Providence as sponsor was criticized by fans and several organizations, including the Emerald City Supporters and the Sounders FC Alliance Council, due to the healthcare system's policies on abortion, transgender care, and treatment of low-income patients.

[240] A new training facility, named the Providence Swedish Performance Center & Clubhouse, opened in February 2024 at an office park in Renton at the site of the former Longacres horse racetrack.

[263][264] The rivalry cup's trophy was commissioned by the Soccer Silicon Valley Community Foundation and designed by a San Jose Earthquakes fan in collaboration with Sounders supporters.

[268] Seattle Reign FC of the National Women's Soccer League has been owned by the Sounders and the Carlyle Group since 2024;[269] Hanauer and his mother Lenore were previously minority owners of the team from 2019 to 2020, though there was no affiliation between the two clubs.

[274] He was replaced by Seattle Futbol Club LLC, formed by 11 families with ties to the Seattle area including former Microsoft executive Terry Myerson and his wife Katie Myerson, Russell Wilson, Ciara, Macklemore and Tricia Davis, Satya Nadella and Anu Nadella, Amy Hood and Max Kleinman, Joe Belfiore and Kristina Belfiore, S. Somasegar and Akila Somasegar, Chee Chew and Christine Chew, David Nathanson and Sabina Nathanson, Brian McAndrews and Elise Holschuh, and Mark Agne and Tomoko Agne.

[278] The team gained three additional part-owners in August 2023, comprising the families of Amazon executive Adam Selipsky, system integration consultant Rick Cantu, and real estate developer Jay Stein.

[286][287] Former Sounders defender Taylor Graham was hired as the club's Vice President of Business Operations in 2012,[288] replacing longtime Seattle Seahawks executive Gary Wright.

[300] The team, initially named Seattle Sounders FC 2 (S2), began play at the Starfire Sports Complex in 2015, under the management of former assistant coach Ezra Hendrickson.

The Sounders established their affiliated academy team in 2010, and hired manager Dick McCormick and technical director Darren Sawatzky to develop local players.

[308][309] Several academy products have been signed by the Sounders under the MLS Homegrown Player Rule, including DeAndre Yedlin, Sean Okoli, Jordan Morris, and Henry Wingo.

[317][318] In June 2024, the Sounders announced their acquisition of National Women's Soccer League side Seattle Reign FC as managing partner alongside the Carlyle Group.