The injury-prone winger spent five seasons at Liverpool but was not offered a new contract at the end of this past season. In 93 appearances for the club, he scored 12 goals.
Kewell's decision to join the Turkish giants comes as a surprise to fans of Leeds United, the club where the 29-year-old began his professional career. In 2000, Kewell and his teammates traveled to Turkey to take on Galatasaray in the first leg of the UEFA Cup semifinals. On the eve of the game, deadly violence erupted in the capital and two Leeds supporters were stabbed to death.
UEFA decided the game would be played, angering Leeds officials. The English club argued the game should be postponed and moved to a neutral site. Galatasaray triumphed over two legs, winning 4-2 on aggregate. Kewell was sent off in the second leg.
Leeds United Supporters' Club chairman Ray Fell was not pleased with the Australian's decision.
"It's disappointing, to put it mildly," he said, "time has passed but there are people in Leeds close to the two lads we lost who will find it harder to move on."
In an open letter to Leeds fans, Kewell explained his choice.
"My love and respect for Leeds United and what the club has done for me will never change," the Australian said, "no matter what anyone says about me and whatever their motives are."
Kewell also said that he selected his number as a tribute to his former club.
"I chose the No. 19 shirt," he said, "when I signed for Galatasaray as a sign of respect for Leeds because that was the number I got when I first became a regular member of the Leeds starting XI."
Kewell, who has 11 international goals in 36 appearances, is excited at the prospect of playing in front of Galatasaray's famous fans.
"I know that the fans are passionate about sport and I love that," he said, "I can't wait to get more of it."