The Spanish club owned by former Houston Astros general manager Jeff Luhnow secured promotion to LaLiga on Sunday.
Leganés beat Elche 2-0 to win the second-division title. Their promotion came four years after they were relegated, and two years after the investment group led by Luhnow bought the modest club based in a neighborhood of southern Madrid.
Leganés finished with 74 points after 42 matches, two points more than Valladolid, the club owned by former Brazil great Ronaldo which had already secured automatic promotion. Valladolid lost 2-1 at Tenerife on Sunday to miss out on the second-division title.
Eibar, the other team with a chance to finish in the top two and avoid a promotion playoff, beat Oviedo 4-3 but ended a point behind Valladolid. They will be in the playoffs along with Oviedo, Sporting Gijon and Espanyol.
Luhnow's Blue Crow Sports Group has included investors from the United States, Mexico, El Salvador, Nicaragua and Canada.
Leganés had been owned since 2008 by a local couple who took over when the club was mired in debt and playing in the third division.
The club earned promotion to the first division for the first time in 2016. Their greatest achievement came in 2017-18 with a win over Real Madrid on their way to reaching the semifinals of the Copa del Rey.
Luhnow and Astros manager AJ Hinch were suspended for one year by Major League Baseball after it was found that the team engineered a sign-stealing scheme using electronics during Houston's run to the 2017 World Series title and again in the 2018 season.
Information from The Associated Press was used in this story.