Joe Fadness, executive director of the Wisconsin Republican Party and one of those named in the emails, criticized American Bridge while refusing to say whether the GOP was undertaking its own review of the documents.
"American Bridge is a desperate attack group funded by billionaire George Soros with the single goal of misleading voters," Fadness said. "While they focus their time on distorted attacks, Republicans under Governor Scott Walker will continue moving Wisconsin forward."
The emails were collected during a criminal investigation into whether Walker's aides were illegally doing campaign work for the 2010 election while being paid as county employees.
The files include thousands of messages to and from Walker as well as key members of his county office and campaign inner circle. They offer a rare insiders' look into both Walker and the daily operations of his gubernatorial campaign.
Walker wasn't charged in the investigation, but it continues to shadow him. The email release is proving to be an unwanted distraction as he mounts his re-election campaign and eyes a possible 2016 run for president.
"This is old news," Walker said Saturday at the National Governors Association meeting, adding the interest in emails is "a lot of hype from our opponents who desperately want to shift the subject away because we have good results."
The governor was targeted in a 2012 recall election prompted by anger over his 2011 law that eliminated collective bargaining for most public employees.
More than 900,000 people signed the recall petition, and their signatures have been posted online in a database now used to vet political candidates, elected officials, co-workers, and sometimes even friends. Last summer, Walker rescinded the appointment of a University of Wisconsin-Platteville student to the UW Board of Regents after the student confirmed he had signed the recall petition.
The email release has sparked similar interest, with the added pull that it includes Walker's supporters as well as opponents and, in some cases, snarky comments about those individuals.
Democratic and Republican staffers and lobbyists whose jobs require them to work with Walker told The Associated Press they had searched for their names, but they wouldn't admit it publicly because they didn't want to jeopardize their relationship with the governor.
State Sen. Jon Erpenbach, D-Middleton, said he hadn't yet searched for his name but knew plenty of people who had. He also expected that Republicans were searching the documents just as avidly.
"They are searching to spin the next little bomb that comes out," he said.
Erpenbach's name does appear in the emails but only in news articles that were forwarded to staffers.
In contrast, a number of emails contain unkind remarks about Mike Tate, the Wisconsin Democratic Party chairman. In one email, Kelly Rindfleisch, who was then Walker's deputy chief of staff, joked to Walker's campaign manager about wanting to take Tate out.