The new format will begin with a shortened transition campaign from February to May 2027 featuring a 14-game regular season, playoffs and MLS Cup final.
The first full season under the new timetable will run from mid-to-late July 2027 through late May 2028, with a midwinter break from mid-December to early February and no league matches in January.
Commissioner Don Garber called the move "one of the most important decisions in our history," saying alignment with global schedules would boost clubs' competitiveness, improve transfer-market activity and ensure the playoffs "take centre stage without interruption".
The calendar change and a new regular-season structure were approved on Thursday at an MLS Board of Governors meeting in Palm Beach, Florida.
MLS said it is still working with the MLS Players Association on a transition plan and will continue reviewing potential adjustments to its playoff format.
Under the new footprint, MLS expects most games to remain within roughly the same weather window as today, and said it intends to limit home dates in northern markets during December and February. The league projects that 91% of matches in 2027–28 will fall within the current season's general timeframe.
'A great step forward'
MLS framed the change around four strategic aims: timing transfer business for the primary summer window; allowing summer signings to settle before league and playoffs; reducing clashes with FIFA international dates and summer tournaments; and placing the playoffs in May, when the domestic sports calendar is less crowded and the weather is milder.
Before approving the shift, MLS conducted a two-year review that began in October 2023 and included feedback from owners, club executives, players, the players' union, partners and fans.
The league said research showed strong support for the move, with 92% of "league soccer viewers" in favour.
The current season highlights why MLS would want to make the change.
The league's playoffs are currently underway and battling for attention amid the NFL season and US college football. Meanwhile, this year's biggest acquisition - Son Heung-min - had to join Los Angeles FC midseason after leaving Tottenham Hotspur earlier in the year.
Prominent figures around US soccer backed the change.
"This is a great step forward for MLS to be on par with the top leagues in the world," said US men's coach Mauricio Pochettino.
"Having managed club teams and now the US National Team, the ability to align with the international calendar will have a huge positive impact for the players, coaches and clubs."
Chicago Fire coach Gregg Berhalter said the shift "helps position MLS on par with the best," while former US captain Clint Dempsey said sharing a timetable with other leagues would leave players "sharper" for national-team duty.