Brookbank will be paid $2.5 million over the two years, according to a source.
"The Hawks were a team I kind of hoped would have some interest," Brookbank said. "They have a good, young team with a lot of potential and they're proven winners and I'm happy to join them and help them get back there."
Brookbank, 31, posted career highs in goals (3) and assists (11) with the Anaheim Ducks last season. He also led the Ducks with a plus-11 rating. He's played in parts of six NHL seasons with the Nashville Predators, New Jersey Devils and the Ducks, spending the last four years in Anaheim.
"I'm just kind of a steady defenseman," he said. "You know what you're going to get out of me. Not anything too flashy. I pride myself on making a good first pass and try to just play hard."
The Hawks ranked 27th in penalty killing last season. Brookbank is hoping to help improve that figure.
"It's one of the things they said they needed, a penalty-killing defenseman," Brookbank said. "I've played penalty kill the past few seasons. It's one of the roles on the team I take pride in."
His brother Wade played for the Hawks' minor league affiliate, the Rockford Icehogs, the last two seasons and helped him with the decision to sign with Chicago.
Brookbank joins a crowded defense which includes six veterans under contract and youngster Dylan Olsen.
"I was told I'd be in that 5-6 range, somewhere in there," Brookbank said. "We'll see how it goes. I hope to play every day but it's obviously up to the coaching staff and (my) performance."
Brookbank dropped the gloves no less than seven times in each of the last four seasons and says he won't shy away from fighting in Chicago.
"I'm just a kind of guy when I play I get into some confrontations here and there," he said.
Brookbank is coming off a two-year deal which paid him a total of $1.5 million.