In the first round of the 2018 Davis Cup, Pütz and Struff beat the Australian duo John Peers and Matthew Ebden to set Germany on its way to victory.

In June 2018, Pütz won his first doubles title on the ATP Tour at the Stuttgart Open with Philipp Petzschner as a wildcard entry.

[2] In May 2019, Pütz won his second doubles title with Frederik Nielsen at the Bavarian International Tennis Championships in Munich.

Seeded sixth, Pütz and Venus reached the quarterfinals of the Australian Open, where they were defeated by eventual champions Thanasi Kokkinakis and Nick Kyrgios.

Pütz won his first Grand Slam tournament at the French Open mixed doubles championship with Miyu Kato.

[12] At the same tournament, he reached the quarterfinals for the third time in doubles with new partner Kevin Krawietz with a win over Romain Arneodo and Sam Weissborn, getting revenge for their loss to the same duo at the 2023 Monte-Carlo Masters six weeks earlier.

[15] At the Australian Open, he reached the quarterfinals for the second time at this tournament with Krawietz[16][17] where they lost to eventual finalists Simone Bolelli and Andrea Vavassori.

[20] Next they reached the quarterfinals at the Monte-Carlo Masters where they lost again to the eventual champions and also unseeded pair of Joran Vliegen and Sander Gillé.

[24] On his debut in the main competition at the ATP Finals with Krawietz, having been alternate twice before, he reached the semifinals defeating Simone Bolelli and Andrea Vavassori.

[28] Pütz and Krawietz reached the final at the Adelaide International, losing to Simone Bolelli and Andrea Vavassori in a deciding champions tiebreak.