On March 12, 2020, the season entered a lengthy suspension due to the COVID-19 pandemic in North America, following the cancellation of several matches.

[3] On May 1, the league announced that players would be allowed to resume individual outdoor training at MLS facilities on May 6.

[5] The tournament included 51 matches in 35 days and over 1,000 players and staff quarantined to a set of hotels at Walt Disney World;[6] it was eventually won by the Portland Timbers, who as a result earned a berth in the 2021 CONCACAF Champions League.

[8] The 2020 season saw the addition of two expansion clubs, Inter Miami CF and Nashville SC, which took Major League Soccer to 26 total teams.

The Philadelphia Union won the Supporters' Shield on the final day of the regular season, the first major trophy in the club's history.

[9] The league's teams incurred an estimated financial loss of $1 billion due to lost ticket sales and additional costs.

Due to travel restrictions between US and Canada the three Canadian teams were relocated to temporary stadiums in the United States starting September 20.

After the tournament, the "first phase" of the regular schedule restart had teams playing in their home markets against only conference opponents for six matches with the intent of finishing a 23-match season.

With the inability for supporters to be in attendance and fill their stadiums with passion, however, we feel as though the current climate goes against the spirit of the Shield.

Individual teams could set their own attendance limits based on their local, regional and state regulations during the pandemic.

Note: Several additional matches had fans in attendance, but official figures have not yet been reported: Sporting Kansas City (8 home matches), Orlando City (8), FC Dallas (2), Philadelphia Union (3), Real Salt Lake (1), and Inter Miami CF (1).

[132] The primary issues negotiated were increased player spending, expanded free agency, and more charter travel.

[134] The first two rounds of the 2020 MLS SuperDraft took place on January 9, 2020, and, unlike previous drafts, was held without a major event ceremony and was instead streamed on Twitter via ESPN.

On July 6, FC Dallas withdrew from the tournament due to ten players and one staff member of the club testing positive for COVID-19,[138] after their opening match was initially postponed.

[139] On July 9, Nashville SC were also withdrawn from the tournament after nine players of the club tested positive for the virus,[140] after their opening match was initially postponed.

[141] Each team played three group stage matches, and those results counted in the 2020 MLS regular season standings.

As MLS is Back Tournament winners, the Portland Timbers earned a spot in the 2021 CONCACAF Champions League.

They replaced the berth previously awarded to the MLS regular season points leader in the conference opposite of the Supporters’ Shield winner.