McCain called Governor Palin the political partner who can best help him to "shake up Washington."
She's a mother of five, has a son in the Army going to Iraq, has a 4-month-old with Downs Syndrome. She's anti-abortion, a member of the NRA, hunts and fishes, was a sports reporter for two Anchorage TV stations and has been Alaska's governor for less than two years.
Her selection surprised many, including the chairman of the Illinois Republican convention delegation. He had to look her up in Wikipedia. But he said he likes what he found.
It's fair to say Palin is largely unknown outside Alaska, but Illinois Republican leaders say her selection is bold and inspired.
"He's sent a great political message in doing this in that he really is about reform. It further validates his maverick status and it's about this party reaching out more broadly," said Illinois Republican Party chairman Andy McKenna.
:Palin has been Alaska's governor for less than two years. Before that, she was the mayor of a small town of about 9,000. She's considered a reformer, a maverick and is meant to appeal to disaffected Hillary Clinton supporters.
"I know Hillary Clinton supporters in Chicago who are extremely upset over the way the primary was handled and even more of the fact that she was not chosen or even vetted for vice president," said Jim Durkin, Illinois GOP delegation chairman.
"A lot of people are going to look at the 72-year-old John McCain and think, 'Gee, he might not live through a term in office and is this lady going to take over?' Who is she?" said Jay Stein.
"Obama's attracting a young crowd and (McCain)'s trying to do the same," said Tyrone Stokes.
Palin is described as an unapologetic reformer.
"She pretty much destroyed the old Republican guard, is very much an ethics reformer like McCain, sold the executive jet, wiped out the Bridge to Nowhere, and now I understand she has an over 80 percent approval rating by voters in Alaska," said Rep. Mark Kirk, (R) Highland Park.
Oftentimes the VP choice can detract rather than help the ticket. Palin may attract women and more social conservatives. But is there really enough time to vet someone who's come out of the blue from Alaska on the national scene?
Chicago's Young Republicans defend her executive experience and emphasize the following themes.
"She's refreshing, she's a maverick just like John McCain. She's an expert on energy policy, coming from Alaska. I think she's what our country needs, fresh face, fresh ideas," said Jeremy Rose, political director, Chicago Young Republicans.
And Rose says Republicans are ready to compete with Democrats on that level. Political experts say both sides are trying to use change or reform as a platform. And both sides can attack the other for what they see as experience, or lack thereof.
"Both sides now have issues they can play with. Unfortunately, both sides are vulnerable to the very same issues they can be going with," said Paul Green, Roosevelt University.
And a woman doesn't necessarily appease Hillary Clinton supporters, like Kevin Conlon, who's hosted Clinton fundraisers at his North Shore home. He calls the choice sophomoric and says McCain's pandering.
"Other than being a woman, I see little or no correlation. Senator Clinton's experience is with a state of 19 million in New York; Alaska has 700,000. There is no comparison. And they are night and day on most of the major issues," said Conlon.
It's a choice voters are now digesting as they focus on the Republicans now and Senator McCain.
"I think it's kind of funny, given a lot of his criticisms of Barack Obama's lack of experience, to have someone a heartbeat away from the presidency as his running mate who has, what seems to be, an equally short resume," said John Mack, Chicago resident.
"I think she'll have a tough time going up against Biden," said Jan Nowak, Evanston resident.. McCain, addressing a raucous crowd of supporters, said he made his decision after looking for a political partner "who can best help me shake up Washington and make it start working again for the people who are counting on us." He added: "I have found the right partner to help me stand up to those who value their privileges over their responsibilities, who put power over principle, and put their interests before your needs." The choice of Palin, 44, could weaken one of McCain's main arguments against Obama: that he lacks the experience needed to be president. Palin is three years younger than Obama and a generation younger than Joe Biden, the Democratic vice presidential candidate. But McCain said Palin was "exactly who I need. She's exactly who this country needs to help us fight the same old Washington politics of me first and country second," he said, explaining a surprising decision three days before the Republicans hold their own national convention in St. Paul, Minnesota. "It turns out that the women of America aren't finished yet," Palin said in a reference to Hillary Rodham Clinton's failed bid for the Democratic nomination, "and we can shatter that glass ceiling once and for all." Traditionally, vice presidential candidates have done little to sway electoral results. McCain's choice, however, has received added attention because he would be the oldest president elected to a first term in U.S. history. He turned 72 on Friday. Obama's campaign quickly questioned Palin's qualifications. "Today, John McCain put the former mayor of a town of 9,000 with zero foreign policy experience a heartbeat away from the presidency," Adrianne Marsh, a spokeswoman for Obama, said in a written statement. Palin, a political reformer, lacks the national profile of Biden, a veteran senator. But she could help McCain muffle Obama's oft-repeated criticism that the Republican had little new to offer the country. She would also be the first female to take the No. 2 spot on the Republican ticket and only the second woman nominated for the job in U.S. history. The first was Geraldine Ferraro who ran on Walter Mondale unsuccessful 1984 Democratic presidential ticket. The choice of Palin could help McCain with a key part of the Republican base, social conservatives, some of whom have been wary of his candidacy. McCain may also hope that it will help him appeal to Democratic women who were disillusioned by Obama's defeat of Clinton, who was vying to become America's first female president. Working against Palin in that regard is that many Democratic women are strong supporters of abortion rights, which she strongly opposes. Palin reached out to Democratic women voters, noting that she was following in Ferraro's footsteps, while praising the "determination and grace" of Clinton, who drew 18 million votes in her unsuccessful run against Obama for the Democratic nomination. McCain has been seen as the underdog in the presidential campaign, given the unpopularity of President George W. Bush, a fellow Republican. But he wiped out Obama's lead in opinion polls ahead of the Democratic convention, pressing the argument that Obama was unprepared to be president. Obama appeared to receive the boost in support that typically follows political convention. A Gallup poll released Friday showed him leading 49 percent to 41 percent. Those figures could change after the Republican convention. As he closed out the Democratic convention, Obama unleashed scathing criticism of McCain. His rival, he said in a speech that was seen by more than 38 million people, offered nothing more than an extension of Bush's "failed policies" that had undercut Americans' prosperity and security. He attacked McCain on the Republican's strongest issue, national security. "The Bush-McCain foreign policy has squandered the legacy that generations of Americans -- Democrats and Republicans -- have built, and we are here to restore that legacy." McCain's spokesman Tucker Bounds was quick with a rebuttal, saying Thursday that the Democrat delivered a "misleading speech that was so fundamentally at odds with the meager record of Barack Obama." "The fact remains: Barack Obama is still not ready to be president," he said. By selecting Palin, McCain passed over several more prominent prospects who had figured in speculation for months -- Minnesota Gov. Tim Pawlenty, former Massachusetts Gov. Mitt Romney and former Pennsylvania Gov. Tom Ridge among them.
The Associated Press contributed to this report.