City hopes the addition of Wilkinson will strengthen the side's defence, which has conceded 31 goals in 17 games this season - the equal second highest in the league.
A member of the Socceroos’ triumphant 2015 Asian Cup Squad, Wilkinson has made 16 appearances for the national team, starting in each of Australia’s three group matches at the 2014 FIFA World Cup in Brazil.
Wilkinson returns to the A-League after first appearing as a foundation player for the Central Coast Mariners, making 172 appearances for the Gosford-based club and captaining the team for five seasons.
After leading the Mariners to the A-League Championship in 2013, Wilkinson moved to South Korean club Jeonbuk Motors, winning two consecutive K-League titles in 2014 and 2015 during a three-year stint in Korea.
City Coach John van’t Schip said Wilkinson’s experience and quality would make him a valuable asset for the team.
“Alex brings with him a lot of experience, having played for the Socceroos and in club football in Asia, and his qualities will help strengthen our defence,” van’t Schip said.
“He is an important addition to the squad having enjoyed success both in the A-League and abroad.”
Wilkinson represents the Club’s fifth acquisition in early 2016, following the additions of goalkeeper Dean Bouzanis, defender Osama Malik and midfielders Nick Fitzgerald and Anthony Caceres.
He will wear the number 2 jersey and will commence training with Melbourne City next week.