The Wales international has signed a four-year contract running until June 2030, becoming David Moyes's fifth summer signing after Merlin Röhl's loan obligation was activated alongside the additions of Hayden Hackney, Tyrique George and Christian Nørgaard.
Johnson, who first made his name at Nottingham Forest, has 45 caps for Wales and represented his country at the 2022 World Cup in Qatar. At club level, the 25-year-old netted Tottenham Hotspur's winner in the 2025 Europa League final against Manchester United before tasting more European glory with Crystal Palace in the Conference League last season.
"I'm so excited to be here. The club speaks for itself — it's a massive club and one that when I first heard of the interest, I immediately wanted to come and be part of it," Johnson told evertontv.
"There were a lot of reasons why I was so keen to join — the manager, the players, the direction the team is going in.
"You can see this is a club that wants to go in the right direction, and I'm a player who wants to go in that direction, too, so it feels like a really good match."
He added that his conversations with Moyes played a big part in the decision.
"I want to come in and show what I can do. The manager spoke to me about getting back to the form that I've shown previously, and that's a massive thing for me — the fact he knows and believes in what I can do. For me, listening to him — a manager who is so experienced and someone who has been so successful — it was really nice to hear.
"I want to bring all of my attributes. First and foremost, I'll work for the team, the fans, and represent the club properly. I know that's something that's definitely appreciated and a non-negotiable here. They can expect that from me. On top of that, I think I can bring speed, goals and everything I've got."
Johnson joined Forest's academy at eight, made his senior debut at 18, and finished as the club's top scorer with 19 goals as they won promotion to the Premier League, before a 2023 switch to Tottenham, where he scored that Europa League final winner. He moved across the capital to Palace in January this year.
The winger, who will wear the number 22 shirt at Goodison Park, revealed his past exploits against Everton had left a lasting impression.
"I've had some personal moments against Everton in the past and I think for those reasons, the Club has always had a little place in my heart. My first Premier League goal came at Goodison Park, so that was very special to me. I remember watching so many Premier League games before that, so to score my first goal in an iconic stadium like that, in a big atmosphere, was incredible."
He was equally effusive about Everton's new home, having played there for Palace last season.
"Now there's a new stadium, which is unbelievable, and one that I played at last season. I remember it being a fierce atmosphere. It's intimidating, it's hostile — and it's everything you'd want from a new stadium. This club has everything to get back into European competition. As players, I think we have to put pressure on ourselves to get the club back there, because that's what the club and the fans deserve to have. Everton is a club that has the ambition to win those trophies — and I believe we can do it."