Hussey, who becomes Albion's fourth new arrival this summer, was released by the Dons at the end of last season.
It was the 24-year-old's second stint with the London club, having been signed from there by Coventry in 2009.
He played 65 games in the Championship and League One during a four-year spell with the Sky Blues.
Hussey's arrival signals the possibility of a new role for last season's established left-back Damien McCrory.
"I see Chris predominantly as a left-back and that may mean that I'm toying with the idea of playing Damo one further forward," said Burton boss Gary Rowett.
"But at the same time, I think Chris can play the forward role as well and, in any case, ideally, you want competition for every position.
"He is equally comfortable going forward and defending, so I think we have a really good player on our hands. He has undoubted quality and, like a lot of our others, he's at the right age to go again, I hope."
Albion are due to travel to Spain for a pre-season training camp and Rowett hopes to tie up at least two more signings before they depart on Sunday.