Mies made his ATP World Tour and Grand Slam debut at the Wimbledon Championships in doubles with partner Kevin Krawietz as a qualifier, where they lost in the third round to the eventual champions Mike Bryan and Jack Sock despite having two match points.

[6] This victory made them the first all-German team in the Open Era to win a Grand Slam title, and the first since Gottfried von Cramm and Henner Henkel in 1937.

[11] Mies and Krawietz successfully defended their French Open title, defeating Mate Pavić and Bruno Soares in the final in straight sets.

At the French Open, Mies finally lost his first doubles match at the tournament when he and Krawietz suffered an upset loss in the first round.

Partnering Alexander Erler, Mies won the doubles title at the 2024 Generali Open Kitzbühel, defeating Constantin Frantzen and Hendrik Jebens in the final.