Alfonso Soriano and Kosuke Fukudome also homered for the Cubs, who swept the four games from the Brewers for the first time since 2003.
Rich Harden picked up his first win as a National Leaguer, giving up a run and six hits in seven innings with nine strikeouts. Eight of eleven runs came after two were out.
Just five days ago, the Cubs and Brewers were tied atop the division. After the sweep, the Brewers are 5-games out, tied with the Cardinals for second place. The Brewers finished 1-6 on the home stand and will face the Braves in Atlanta tonight.
The Cubs and Brewers will face each other six of the last 12 games this season, including the final three-game series at Miller Park.