Berrios has been involved in Democratic politics since he was a teenager. He's a member of the county's tax appeals board.
He's also faced criticism for his relatives' jobs and alleged tax breaks for friends and political donors.
Claypool conceded Tuesday evening. He's a county commissioner who was the former chief of staff for Mayor Richard M. Daley.
Cook County Assessor Jim Houlihan is retiring.
Berrios was accused of playing politics the old way. But that didn't seem to matter. Berrios a Democrat garnered about 48 percent of the vote and will be the Cook County assessor.
Berrios said there was an element of racism in the race. Berrios said he believed it was typical of when minority people try to reach higher office.
Berrios said that in winning this role, he will relinquish his role as a lobbyist in Springfield and dismissed criticism leveled at him by the newspapers. The Chicago Tribune called him a walking conflict of interest.
"I've said from day one that I would give up my lobbying business as assessor, which I committed to do and I will do. I will work 24/7 to make sure I get the assessor's office working correctly for every taxpayer in Cook County," Berrios said.
Berrios said he doesn't know when the second property tax bill for this year will go out, but when it goes out, it will be more transparent than ever in terms of what goes into it and how much money people are paying, and Berrios promises to do the best job he can for all Cook County taxpayers.
Meanwhile, Claypool and his supporters hadhoped they would make history to be the first independent candidate in 108 years to win a Cook county office. Despite the support for Claypool, the Republican candidate Strobeck-Eckersall got a surprising number of votes.
"It's never easy to lose. But sometimes there can be victory in defeat. And the way to do that is, I think, what we've done in this campaign. You plant seeds, and we planted seeds, seeds that will grow and be harvested by others," Claypool said.
Claypool said he may not continue in politics after this race.
"I will always be active in fighting for my beliefs and those beliefs are rooted in the need to stand up to abusive, concentrated government power and in Chicago, Illinois, we have a clique of insiders that have led us to the highest taxes in the country," Claypool said.
The Associated Press contributed to this report.