The versatile United States international has signed a contract until the summer of 2027 and reunites with Leeds boss Jesse Marsch, who managed him at the start of his career at New York Red Bulls and again at RB Leipzig.
Adams is Leeds United's fifth summer signing following the arrivals of Rasmus Kristensen, Brenden Aaronson, Marc Roca and Darko Gyabi.
The 23-year-old will likely come in as a replacement for Kalvin Phillips, who joined Manchester City earlier this week for £45m.
“I am super excited,” Adams told LUTV.
“Walking in for the first time, meeting people today at the training ground and coming to the stadium, which is empty now, but I can’t wait to play in front of a full crowd!
“I know a little bit about the club. I watched the documentary which is quite popular and I was able to learn a lot of important things about the club.
“The one thing for me is the passion of the fans and the city, what it requires to be a Leeds United player.
“So far what I have heard is that it’s electric here. Talking to my friends who have played in the Premier League, they say it’s one of the best atmospheres they have ever played in.
“Now to have those fans supporting me, it’s going to be something special.”
Adams spent three-and-a-half seasons with Leipzig, winning the DFB-Pokal last season.
He has won 30 caps so far for the US national team.
