Pickford has signed a five-year contract and moves to Goodison Park for an initial £25m fee which could rise to £30m depending on team and individual performances.
The 23-year-old made his first-team debut with Sunderland in January 2016 and finished last campaign with the club’s Player of the Season award.
Pickford told evertonfc.com: “It’s great to sign for the club.
“Last season was my first in the Premier League so to get this opportunity with Everton now, to be able to go forward with my career and show everyone what I can do is unbelievable.”
Having suffered relegation with Sunderland, Pickford is glad to be back in the top-flight so soon.
He said: “It’s a great club, a massive club and I think it’s a great opportunity and the right time for me to come to Everton and show what I can do.
“This is an exciting time for the club and for me, too, with the ambition being shown. I just want to be the best I can be to help.”
Pickford was nominated for the PFA Young Player of the Year award despite featuring for a team that finished bottom of the top-flight table.
He earned a call-up to England’s senior ranks in October and has represented the country at each of the six youth levels from Under-16 upwards.
Pickford came through Sunderland’s academy system and had a series of loan deals with the likes of Preston, Bradford, and Carlisle prior to becoming his boyhood club’s number one last term.
The fee is short of the £35million Manchester City parted with earlier this summer to land Brazilian stopper Ederson – but still makes Pickford the most expensive British goalkeeper ever.
That honour currently belongs to Southampton’s Fraser Forster, who Saints paid £10million for when Koeman was in charge on the south coast in 2014.