The 21 year-old began his career at Sutherland Sharks in Sydney's south, before leaving for Europe at the age of 17.
The Sydney-born defender played in Italy before joining Tottenham Hotspur for two and a half seasons in the U-21 Premier League.
He then moved to Swansea City for one season, winning the 2014-2015 Development League Two title with the Swans.
Melbourne Victory coach Kevin Muscat said he was pleased to secure Gallifuoco's signature and said he will bring a number of qualities to the club.
"Giancarlo adds depth to our squad in defence and will also add further competition for spots in our team, which is healthy," Muscat said.
"He has gained valuable experience in England over the past few seasons and is a member of the Olyroos squad aiming to qualify for Rio 2016, so he is fit and ready to get into it."
Gallifuoco said the opportunity to join the A-League champion was a defining factor in his decision to return home.
"I knew coming to Melbourne Victory I was going to be around winners and people that demand the best and they are the best people to be associated with," Gallifuoco said.
"The club has the correct professionalism and the players have the correct attitude and they're the people I want to be around every day.
"I really enjoyed it at Swansea, I was able to be captain and we won the league, but I thought this was the best move for me."
