It is now the fourth time both of Chicago's teams have made the Postseason together and the third time overall in a full season. The last time they did was in 2020 during the COVID season, with the other two times being in 2008 and 1906.
Within minutes of one another, the Windy City rivals became the seventh and eighth teams to book October baseball. Three of the remaining four slots could also be settled Thursday.
The White Sox crowned an extraordinary turnaround season, securing at least a wild card spot after losing more than 100 games in each of their previous three seasons.
They did so in emphatic style, routing the Kansas City Royals 9-1. The White Sox scored three runs in each of their first two innings, before a Kyle Teel home run in the fourth left little doubt.
Chicago shortstop Colson Montgomery equaled the unwanted record for the most strikeouts in an MLB season, with his 223rd time on Thursday -- tying the Arizona Diamondbacks' Mark Reynolds in 2009.
Still, the White Sox will now make their first post-season appearance since winning the American League Central division title in 2021.
They are neck-and-neck with the Cleveland Guardians to top the division this season with three games still to play.
Meanwhile, the Cubs edged the Miami Marlins 2-1 to claim their own wild card spot in the National League.
A stolen base in the first inning by Pete Crow-Armstrong made him the seventh player with 40 homers and 40 stolen bases in a season. He has 45 homers this season.
Miami opened the scoring in the third inning, but a Seiya Suzuki homer in the fifth got the Cubs back on track.
Ian Happ scored from a Nico Hoerner single the very next inning, and the Cubs held out for the win.
Other teams that can book their postseason berths Thursday include the Guardians, San Diego Padres and Philadelphia Phillies.
Six teams have already clinched: the Los Angeles Dodgers, New York Yankees, Boston Red Sox, Tampa Bay Rays, Milwaukee Brewers and Atlanta Braves.
MAJOR LEAGUE BASEBALL
The MLB regular season is now in its final two months as the countdown to the Postseason begins!