The 6ft 4ins tall Canadian played a big part in helping the Giants take last season's Elite League title with 10 games still to play, posting six goals and 24 assists for 30 points in 63 games.
Brookwell joins Calvin Elfring, Jeff Mason, Davey Phillips, Kevin Phillips and Robby Sandrock on the blue line, completing the team's same defence for a second season running.
"We are really excited to have our full D-corps back as it was one of last season's strengths," Head of Hockey Steve Thornton said.
"Having D-men who can make decisions and can move the puck will be more critical this season and that's what we have."
The new season will be Thornton's first coaching Brookwell, but he's already aware of the important role he will play in the team.
"With the extra import rule this season, it seems to have created more size in the league and it was important to have a big body to create some room in front of the net, be physical in the corners, and still have ability to have quick feet and make that outlet pass," he said.
"That's a rare combination for a big man, but that's what Cody has."