Left-back Behich kickstarted his career across 89 games for Melbourne Heart, now City, between 2010 and 2013.
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The 32-year-old has 57 caps and played every minute of last year's World Cup campaign with the Socceroos. He replaces young gun and current Socceroos left-back Jordan Bos, who has moved to Belgium, at City.
"It's exciting to be back in my hometown, with my friends and family and preparing for a new season with a club that is so close to my heart," Behich said in a statement.
"Aziz perfectly suits the City style of football and character that we require," City football director Michael Petrillo said in a statement. "He has a great attitude, works hard and is very good in both attacking and defensive phases. He will bring further leadership qualities to our group and will be a positive mentor for our younger players.
"Aziz had an outstanding tournament at last year's World Cup. We look forward to him bringing his skill, passion, and competitiveness to the pitch over the next two seasons."