Keith signed a contract with the Chicago Blackhawks for the 2003-04 season and spent his first two season tuning up his game at their AHL affiliate Norfolk Admirals logging heavy minutes and scoring 51 points in 154 games. He got his first call up to the NHL on October 5th, 2005 against the Anaheim Ducks. Following 2 seasons in the AHL, he made the Blackhawk squad out of the 2006 training camp He made an immediate impact on the club by averaging over 23 minutes of ice time in 81 games that season.

 

At the conclusion of the 2005-06 season he was rewarded for his stellar play by the Blackhawks who signed him to a five year extension of his contract. For the 2006-07 season he would play in all 82 games for the Blackhawks and once again lead the time in minutes played averaging over 23 minutes a game again. He had 31 points with 29 assists and 2 goals, plus he led the team in blocked shots with 148. For the 2007-08 season, Keith would see even more ice time after injuries wracked the Blackhawk defensive core. By mid January, he was averaging 24:31 ice time per game and had a team leading plus/minus of +14. He was rewarded for this effort by a selection to the 2008 NHL All Star Game.