The 24-year-old completed his move from Burnley on Monday and signed a five-year contract at the club for a fee which could rise to a record-equalling £30m.
Keane joins Jordan Pickford, Davy Klaassen, Henry Onyekuru and Sandro Ramirez, who have all joined the club recently, and he cannot wait to get started.
He said: “I’m absolutely delighted to be at Everton, a fantastic football club with passionate fans and a great tradition and I can’t wait to come into training tomorrow to meet all the lads.
“First and foremost, the manager was a big factor in me coming to the club.
“He played in my position when he was a world-class player for a great Barcelona side and a great Dutch side and the style of football he likes to play will suit me, I believe.
“He’s convinced me that he can still improve me in certain areas of my game.”