He added: “The Real Madrid fans are excited to begin this new era, to grow, and to make the history of this club even greater.
“It’s a special day. It’s a day I will have marked in my calendar for life. I am very happy to be here, in what I feel is my home.”
Alonso, who won a league and cup double with Bayer Leverkusen in 2023-24, explained his decision to return to Madrid 11 years after he left the club as a player.
“We have fantastic players, we have a team that has a lot of potential, [capable of] a very good present and a very good future,” he said.
“That gives me a lot of reason to come here with a lot of energy and a lot of hope that I can get the best out of all the players and build a great team.
“[I have] the conviction that we can achieve big things, worthy of Real Madrid, worthy of all these European Cups, of all these accomplishments made over so many years.
“I want a team that transmits emotion, energy, ambitious play and connects with the fans.”
Alonso paid tribute to Ancelotti – who won three Champions Leagues, two Club World Cups and two La Liga titles across two spells with Los Blancos – and also managed Alonso at both Real and Bayern Munich.
“Carlo was my coach, a great person and a huge influence. Without his mastery, I probably wouldn’t be here,” he said.
“I take over and carry on his legacy with great honour and pride.”
Alonso will begin his tenure on 1 June, before the Fifa Club World Cup next month.