"I will be honored to accept the nomination for vice president of the United States," she said in the convention's most anticipated speech. The 44-year-old, self-described "hockey mom" still awaits formal nomination for the second spot on the ticket.
After Palin's speech, McCain officially became the Republican nominee. The late-night roll call vote came to a climax when the delegates from McCain's home state of Arizona put him over the top.
McCain is scheduled to accept the nomination in a speech Thursday night. If elected, the 72-year-old McCain would be the oldest first-term president.
Palin pledged that as McCain's running mate, she wanted to go to Washington not to seek the media's approval but "to serve the people of this great country."
Depicting herself as "just your average hockey mom," Palin described her political career as mayor of her small town before her election as governor.
"Since our opponents in this presidential election seem to look down on that experience, let me explain to them what the job involves," Palin said. "I guess a small-town mayor is sort of like a `community organizer,' except that you have actual responsibilities."
Palin took crowd-delighting swipes at Democratic presidential nomineeand what she called the "Washington elite."
"The American presidency is not supposed to be a journey of 'personal discovery.' This world of threats and dangers is not just a community, and it doesn't just need an organizer," Palin said, a clear reference to Obama's time as a community organizer in Chicago.
After her speech, McCain briefly joined Palin on stage.
"Don't you think we made the right choice for the next vice president of the United States," McCain asked to a thunderous ovation.
Selected by McCain last Friday, Palin addressed the convention amid questions about her qualifications and relative lack of experience.
The first-term governor had top billing on a night delegates also lined up for a noisy roll call of the states to deliver their presidential nomination to McCain.
"The question remains whether her performance was enough to win over the 60 percent of the nation who say they don't know enough about her to have an opinion," said CBSNews.com senior political editor Vaughn Ververs. "But by almost any measure, her performance exceeded expectations."
(to read Ververs' full analysis)
Watching her from inside the convention hall were members of Palin's family, including husband Todd, and their children, including 17-year-old Bristol Palin, whom the Palins disclosed earlier in the week was five months pregnant. Bristol Palin's 18-year-old boyfriend and apparent fiance, Levi Johnston, was seated with them.
Noting that the couple's oldest son, Track, 19, was shipping out to Iraq in eight days with the Army infantry, Palin praised McCain as "a true profile in courage, and people like that are hard to come by."
"He's a man who wore the uniform of this country for 22 years, and refused to break faith with those troops in Iraq who have now brought victory within sight. And as the mother of one of those troops, that is exactly the kind of man I want as commander in chief," she said.
Largely unknown outside her home state, Palin told the convention: "I had the privilege of living most of my life in a small town. I was just your average hockey mom, and signed up for the PTA because I wanted to make my kids' public education better," she said, speaking of her home town of Wasilla, Alaska, with a population of about 6,500.
Palin said she was not part of the permanent "Washington elite." She said some in the media think that makes her unqualified.
"Here's a little news flash for all those reporters and commentators: I'm not going to Washington to seek their good opinion - I'm going to Washington to serve the people of the country," Palin said.
The speech was the first-term Alaska governor's first chance to fully introduce and define herself to the American public.
"Here's how I look at the choice Americans face in this election," she said. "In politics, there are some candidates who use change to promote their careers. And then there are those like John McCain, who use their careers to promote change." It was another indirect dig at the Democratic presidential nominee.
"When I ran for city council, I didn't need focus groups and voter profiles because I knew those voters, and knew their families, too," she said.
Before Palin's big speech, vanquished Republican presidential hopefuls Rudy Giuliani, Mike Huckabee and Mitt Romney got enthusiastic greetings when they took turns speaking to delegates.
Giuliani, the former New York City mayor, praised Palin as "one of the most successful governors in America - and the most popular."
(Read theand watch
She's been governor for two years, after eight as mayor of tiny Wasilla, but Giuliani said she's ready for the vice presidency. "She already has more executive experience than the entire Democratic ticket," he said.
Giuliani was the early leader among Republican candidates in the presidential race, but he foundered quickly and quit the race without winning a delegate, endorsing McCain in January. Romney and then Huckabee did the same.
The McCain campaign had announced that Giuliani would be the keynote speaker at the convention, and he was to have spoken Tuesday night in that role. But the schedule was shuffled and most of its opening day was dropped because of the threat of Hurricane Gustav to the Gulf Coast.
Before Giuliani's speech, Mike Huckabee--another former governor who challenged McCain for the Republican nomination--took the stage.
Huckabee said that the heavy media scrutiny of the party, especially over Palin, had the effect of unifying the GOP. He said news media coverage has been "tackier than a costume change at a Madonna concert."
(Read theand watch
Republicans have been chafing over a wide array of questions that reporters have raised this week over the process by which Palin was vetted, her family and her record as a mayor and governor in Alaska.
The first of the three former McCain rivals to speak on Wednesday, Romney said Washington is dominated by liberal politics and asserted that people are tired of it. The Michigan native said the country needs change "from a liberal Washington to a conservative Washington."
(Read theand watch
Romney unsuccessfully challenged McCain for his party's presidential nod. The former Massachusetts governor said Wednesday night that the prescription for people wanting change is to "throw out the liberal government in Washington and elect John McCain and Sarah Palin."