Nagelsmann, who signed a contract extension in January 2025 through the 2028 European Championship, initially stated he would not step down but later changed his position.
"My top priority has always been the team's success," Nagelsmann said in a DFB statement.
The 38-year-old manager, who succeeded Hansi Flick in September 2023, expressed gratitude toward his staff and the federation.
"I want to thank my coaching staff, the support team, and everyone at the federation who supported us, especially the players with whom I had the privilege of working," Nagelsmann said.
He also acknowledged the disappointment felt by German supporters: "It truly pains me that we disappointed you and couldn't give you any more memorable nights of football at this World Cup.
You deserved so much more!"
The tournament exit represented a historic low for Germany, as the nation suffered its first-ever World Cup penalty shootout loss after winning all four previous shootouts.
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Following the elimination, 40-year-old goalkeeper Manuel Neuer confirmed his second and final retirement from international football after earning 128 caps.
