Everton secured Hayden Hackney from Middlesbrough in a transfer deal worth up to £24 million.
The 24-year-old midfielder signed a five-year contract after being named the 2025-26 Championship Player of the Season.
Hackney is an England U21 international who chose Everton over other interested Premier League clubs.
Manager David Moyes identified Hackney as a priority signing to provide midfield competition for the new campaign.