The group United Wisconsin, which opposes the collective bargaining changes and other measures Walker pushed into law last year, said it gathered more than 1 million signatures to recall the governor by the January 17 deadline -- roughly double the 540,208 signatures required.
The signatures represent about a quarter of all votes cast in the state in the 2010 election that brought Walker to power -- a reminder of both the controversy that surrounds the 44-year-old governor and the deep divisions within Wisconsin as it moves into a second round of recall elections triggered by the collective bargaining fight.
The petitions arrived in the state capital on Tuesday in a U-Haul truck decorated with a banner that read, "We did it for Wisconsin's future."
Julie Wells, the factory worker and grandmother who helped trigger the recall effort, took the first of more than 150 boxes into the Government Accountability Board's offices.
"What we have done over the past 60 days for the state of Wisconsin is monumental," Wells told a crowd of about 400 recall supporters.
The petitions must be certified, but with a gubernatorial recall election increasingly likely, Walker faces the prospect of becoming just the third governor in history to be recalled.
Still, Wisconsin remains remarkably split and it is possible that Walker could survive a special election.
Last summer, after forging ahead with an agenda that included the successful passage of voter ID and concealed carry legislation, six Republican senators faced recall. Ultimately, only two were recalled.
In a statement, Brad Courtney, the chairman of the Republican Party of Wisconsin, called the latest recall effort "shameful" and predicted it would "accomplish nothing but saddle Wisconsin taxpayers with over $9 million in unbudgeted costs" related to the special election.
So far, no Democrat has emerged to run against Walker, though Milwaukee Mayor Tom Barrett, who ran for governor against Walker in 2010 and Secretary of State Doug La Follette have been mentioned as possible candidates.
"We very clearly believe there is no challenge -- legal or otherwise -- that would prevent these elections from going forward," said Mike Tate, the head of the Democratic Party of Wisconsin.
As many as 17 Wisconsin state senators -- 11 Republicans and six Democrats -- could face special recall elections this year in contests triggered by last year's fight over union rights and other Republican-backed measures.
Indeed recall organizers on Tuesday also submitted what they said were enough recall petitions to force four Republican state senators, including Senate majority leader Scott Fitzgerald, as well as Lieutenant Governor Rebecca Kleefisch, into special elections defending their seats later this year.
The elections could tip the balance of power in the state Senate, where Republicans currently hold a 17-16 majority.
But they may also provide an early glimpse of how closely fought the 2012 presidential race will be in key Midwestern states like Wisconsin, where voters backed Barack Obama in 2008 but handed victories to Republicans in the 2010 midterms.
In a statement, Walker seemed to accept that the recall drive would be certified and a special election scheduled.
"I look forward to talking to the people of Wisconsin about my continued promises to control government spending, balance the budget, and hold the line on taxes," he said.
Officials at the state's Government Accountability Board said last week they may need more than 60 days to verify the signatures submitted on Tuesday. Currently, the law requires the process to be completed in 31 days.
According to a Government Accountability Board report, processing recall petitions will cost the state more than $650,000. The total cost of recall elections for the state and municipalities may be more than $9 million, according to estimates from board officials.
(Reporting by Brendan O'Brien; Writing by James B. Kelleher; editing by Paul Thomasch)