Everton boss David Moyes confirmed on Friday that the club was in talks to sign the 27-year-old on a free transfer.
Mucha has now signed a three-year deal with Everton and will join the club when his contract with Legia Warsaw expires at the end of the season.
“It makes me happy to know that Slovakia will have their first goalkeeper ever in the Premier League,” Mucha’s agent Jozef Tokos told SITA.
“Janko deserves this move for his long-term excellent performances both at international and club level.
“He also had offers from Italy, France and Turkey but has decided not to take the most lucrative one. His priority has been the sporting side of things and Everton is the best one.
“He is going to compete with Tim Howard for the position of first-choice goalkeeper, but I am convinced he can gain ground there.”
