Berrios took about 46 percent of the vote with 60 percent of precincts reporting.
The first Hispanic elected to office in Chicago, Berrios managed to edge out his main competitor and former fellow Democrat Claypool by 13 percentage points. It's a big win for the Democrats who were faced with the threat of losing the position after the mess created by Todd Stroger.
Claypool conceded earlier in the evening.
"I't's never easy to lose, but sometimes there can be victory in defeat," Claypool said.
Berrios plans to fairly assess properties at market value, incorporate new technology to ensure accurate assessments, and improve customer service.