Winger Savinho says "it's taken a while" but he is "very happy" to have signed for Tottenham.
The 22-year-old's move to north London has been more than 12 months in the making, with Spurs failing in a bid to sign him last summer.
"It's a wonderful opportunity at a brilliant club with one of the best managers in the world," said Savinho.
"As soon as I spoke to the head coach, I knew I had to come. He told me he wants to help me reach the highest level, and I believe we can do that together, as a team."
De Zerbi added: "Savio is a player who brings energy, imagination and quality in wide positions. He has the courage to attack defenders and the ability to change a game with his creativity.
"We're very pleased to have him with us, and I'm looking forward to working with him, helping him continue to grow and seeing him bring his personality to the team."
Savinho joined Manchester City from French side Troyes in 2024, but his game time was limited under Pep Guardiola last term when he made just seven Premier League starts.
Spurs sporting director Johan Lange said the Brazilian "will excite our supporters every time he gets on the ball", adding: "He has already shown his quality at the highest level and we believe his ability, style and mentality will be a great fit for the squad we are building here.
"I'm looking forward to watching his development under Roberto's coaching."