He has signed a three-and-a-half-year contract.
Alan Pardew: "I am absolutely delighted to be the new manager of Crystal Palace.
"Everyone knows my history here, what's important now is to move the club to the next level.
"I believe with the backing of Steve (Parish) and the board I can help achieve that and create some new exciting history for the club.
"It's been a privilege to manage Newcastle United and I want to thank my captain, Fabricio Coloccini, and all the players, John Carver, Steve Stone, Andy Woodman and all the staff, all of whom have been outstanding servants to Newcastle United.
"A special thanks also goes to the fans for all their support over the last four years.
"I must also thank Mike Ashley and the board for their unwavering support during my tenure at the club."
Chairman Parish: "We wanted a manager with a great track record and proven experience in the Barclays Premier League.
"In Alan we have both these things as well as a man who has great affection for this club and shares my determination to take us to the next level."