Kewell, 35, on Wednesday said he will play his last professional match on April 12 when he captains the Melbourne Heart against Western Sydney Wanderers.
Kewell became the youngest player to appear for Australia when he made his debut against Chile in 1996 aged 17 years, 7 months. Playing mostly as an attacking midfielder, scored 17 goals in 56 internationals, appearing at the 2006 and 2010 World Cups.
Kewell scored 45 goals in 181 matches for Leeds and 12 in 98 appearances for Liverpool. He went on to play 63 games for the Turkish club Galatasaray, scoring 22 goals.
He accepted he was likely not being considered for the World Cup by Australia coach Ange Postecoglou and a recent rib injury snuffed out even the faintest hope he might be selected.
"For the World Cup I can sit back and enjoy it," Kewell said. "There's obviously going to be questions asked about the World Cup, but I haven't been part of the Australian squad for a while.
"For me it was time to step aside and let young players stand up."
Former Australia and Manchester United goalkeeper Mark Bosnich said Kewell would be remembered as "one of Australia's greatest players ever."
"He's done the admirable thing by retiring now," Bosnich said.