The ex-Roar skipper has put pen to paper on a new deal with his former club after parting ways with Changchun Yatai last month
McKay had spent the last two years overseas playing in China and Korea, as well as with famous Scottish side Rangers.
But the 30-year-old was released by Chinese Super League outfit Changchun Yatai last month, after just six months at the club, and the 41-time Australian international said he was thrilled to be returning to the team he captained to the A-League premiership-championship double in the 2010-11 season.
"I'm very happy to be back in Brisbane and back at the Roar," McKay said on Sunday.
"This club and this city is so close to my heart and I'm really looking forward to that moment when I pull on the orange jersey again and walk out onto Suncorp Stadium."
McKay's new deal will take him through until the end of the 2014-15 season.
Brisbane head coach Mike Mulvey said the capture of McKay as the club's Australian marquee player would be a boost for the Roar.
"Having a leader like Matt coming into such a competitive team will lift the bar across the whole squad," Mulvey said.
McKay joined Changchun in January in what was his second stint with the side after he was loaned to them by Brisbane in 2009.
But after just 11 games, McKay parted ways with the Chinese outfit.
McKay linked up with Changchun after almost a year with K-League club Busan I'Park and a season with Rangers.
Before his international football foray, McKay spent six seasons with the Roar, playing 131 matches for Brisbane.