Wanderers, who had been in talks with former Germany skipper Michael Ballack, said the gifted but injury-prone player had agreed to join the club from J.League outfit Shimizu S-Pulse for at least one season.
Ono, who played 56 times for his country and featured at three World Cups, follows Italian World Cup winner Alessandro Del Piero and former England striker Emile Heskey in signing up to play in Australia.
"Shinji's class and professionalism will rub off on all the young players we have," club chairman Lyall Gorman said.
"The added benefit is the international profile Shinji will bring to the Wanderers and give us another way to connect with fans across western Sydney."
As well as two spells at the Urawa Red Diamonds, 33-year-old Ono played for four years with Dutch club Feyenoord - where he won a UEFA Cup winners medal - and two years with German club Bochum.
Del Piero will become the highest-profile player to compete in the A-league after he joined Sydney FC in a deal worth A$2 million (1.3 million pounds) a year earlier this month.
Heskey, who played 62 times for England, arrived at Sydney airport on Friday morning to begin his spell with the Newcastle Jets further up the New South Wales coast.
The eighth A-League season kicks off on October 5 with a Melbourne derby between the Victory and the Heart at the Docklands Stadium. The Wanderers play their first match a day later, at home to the Central Coast Mariners.