"Tonight, I have a privilege given few Americans -- the privilege of accepting our party's nomination for President of the United States," McCain said as the crowd broke into chants of "USA! USA!"
"And I accept it with gratitude, humility and confidence," McCain said.
McCain, a POW turned political rebel, vowed Thursday night to vanquish the "constant partisan rancor" that grips Washington as he launched his fall campaign for the White House. "Change is coming," he promised the roaring Republican National Convention and a prime-time television audience.
"Fight with me. Fight with me. Fight with me. Fight for what's right for our country," he urged in a convention crescendo.
To repeated cheers from his delegates, McCain made only passing reference to an unpopular George W. Bush and criticized fellow Republicans as well as Democratic rivalin reaching out to independents and swing voters who will pick the next president.
"We were elected to change Washington, and we let Washington change us," he said of the Republicans who controlled Congress for a dozen years before they were voted out of office in 2006.
As for Obama, he said, "I will keep taxes low and cut them where I can. My opponent will raise them. I will cut government spending. He will increase it."
"Appropriating Barack Obama's own message may seem like a brazen political ploy, but for McCain, it's less of a stretch than it would be for most other Republicans," said CBSNews.com senior political editor Vaughn Ververs. "As he and the rest of the speakers here in St. Paul emphasized over and over, McCain sees himself as a 'maverick' politician whose past political fights have been waged as much within his own party as without. And it's that reputation - one which has enraged Republicans at times - which now become's the GOP battle cry."
McCain's wife, Cindy, and ticketmateand her husband joined him on stage as tens of thousands red, white and blue balloons cascaded from high above the convention floor.
Unlike Obama's speech a week ago, McCain offered no soaring oratory until his speech-ending summons to fight for the country's future.
But his own measured style left the hall in cheers, and as is his habit in campaign stops around the country, he stepped off the stage to plunge into the crowd after his speech. Palin joined him, embraced by the jubilant throng.
McCain touched only briefly on the Iraq war - a conflict that Obama has vowed to end. "I fought for the right strategy and more troops in Iraq, when it wasn't a popular thing to do," the Republican said, adding that in the months since, the long-suffering nation had been spared from defeat. McCain's appearance was the climax of the final night of the party convention, coming after delegates made Palin the first female vice presidential nominee in Republican history.
"She stands up for what's right and she doesn't let anyone tell her to sit down," McCain said of the woman who has faced intense scrutiny in the week since she was picked.
"And let me offer an advance warning to the old, big-spending, do-nothing, me-first, country-second Washington crowd: Change is coming," McCain declared.
McCain and Palin were departing their convention city immediately after the Arizona senator's acceptance speech, bound for Wisconsin and an early start on the final weeks of the White House campaign.
McCain, at 72 bidding to become the oldest first-term president, drew a roar from the convention crowd when he walked out onto the stage lighted by a single spotlight. He was introduced by a video that dwelt heavily on his time spent as a prisoner of war in Vietnam and as a member of Congress, hailed for a "faithful unyielding love for America, country first."
McCain faced a delicate assignment as he formally accepted his party's presidential nomination: presenting his credentials as a reformer willing to take on his own party and stressing his independence from an unpopular President Bush - all without breaking faith with his Republican base.
He set about it methodically.
"After we've won, we're going to reach out our hand to any willing patriot, make this government start working for you again," he said, and he pledged to invite Democrats and independents to serve in his administration.
He mentioned Mr. Bush only in passing, as the leader who led the country through the days after the terror attacks on Sept. 11, 2001.
And there was plenty for conservative Republicans to cheer - from his pledge to free the country from the grip of its dependence on foreign oil, to a vow to have schools answer to parents and students rather than "unions and entrenched bureaucrats."
A man who has clashed repeatedly with Republicans in Congress, he said proudly, "I've been called a maverick. Sometimes it's meant as a compliment and sometimes it's not. What it really means is I understand who I work for.
"I don't work for a party. I don't work for a special interest. I don't work for myself. I work for you."
Thousands of red, white and blue balloons nestled in netting above the convention floor, to be released on cue for the traditional celebratory convention finale.
Given McCain's political mission, it was left to other Republicans to deliver much of the criticism aimed at Obama.
In the race for the White House, "It's not about building a record, it's about having one," said former Pennsylvania Gov. Tom Ridge. "It's not about talking pretty, it's about talking straight."
McCain invoked the five years he spent in a North Vietnamese prison. "I fell in love with my country when I was a prisoner in someone else's," he said. "I was never the same again. I wasn't my own man anymore. I was my country's."
The last night of the McCain-Palin convention also marked the end of an intensive stretch of politics with the potential to reshape the race for the White House. Democrats held their own convention last week in Denver, nominating Delaware Sen.as running mate for Obama, whose own acceptance speech drew an estimated 84,000 partisans to an outdoor football stadium.
Before McCain accepted the nomination, his wife Cindy McCain took the stage to urge support for people caught up in Hurricane Gustav and introduced their seven children to the cheering delegates.
"He has shown the value of self-sacrifice by daily example and, above all John showers us with the unconditional love and support every family dreams of. I know what his children say of him," Cindy McCain said. "And his courageous service to America in war and peace leaves no doubt what our forefathers would make of him."
(Read theand watch
Ahead lie the traditional major checkpoints - presidential and vice presidential debates, millions of dollars in ads - but also the unscripted, spontaneous moments that can take on outsized importance in the race to pick a president.
Sen. Lindsey Graham, R-S.C., also had a speaking slot, and he used it to criticize McCain's rival. He said Obama and the liberal group MoveOn.org were the only ones who didn't realize that Bush's decision to deploy additional troops to Iraq last year had succeeded.
Ridge's turn at the podium came after he had been mentioned prominently in speculation about a running mate.
That was an honor that went unexpectedly to Palin, the first female vice presidential candidate in party history, a 44-year-old Alaska governor virtually unknown nationally a week ago.
In the days since, she has faced a storm of scrutiny, some of it relating to her tenure as mayor of Wasilla, Alaska, and her time as governor, but most involving her 17-year-old unmarried daughter who is pregnant.
For the most part, McCain's aides have kept Palin out of public sight while vociferously defending her readiness to become president. She emerged Wednesday night during prime time to deliver a smiling, sarcastic attack on Obama that generated roars of approval - and acceptance - from the delegates.
She followed up in the hours before McCain's convention appearance with a meeting with Republican governors and a fundraising appeal that blamed Democrats for spreading "misinformation and flat-out lies" about her family and her.
Even so, there were fresh questions about her readiness to sit one chair away from the Oval Office.
McCain has cited her authority over the Alaska National Guard as one example. But in a memo last spring, Air Force Maj. Gen. Craig Campbell warned that "missions are at risk" in the state's units because of a personnel shortage. The lack of qualified airmen, Campbell said, "has reached a crisis level."
In an interview on Wednesday with The Associated Press, Campbell said the situation has improved since then, but not enough to eliminate his concern that shortages will result in the burnout of troops.
McCain won the presidential nomination late Wednesday night in an anticlimactic vote that followed a campaign lasting most of a decade. He first ran for the White House in 2000, but lost the Republican nomination to Bush in a bruising struggle. He began the current campaign the Republican front-runner, but his chances seemed to collapse last winter when opposition to the Iraq war rose among independents and conservatives grew upset over his backing for legislation to give illegal immigrants a path toward citizenship.
In one of the most remarkable comebacks in recent times, he recovered to win the New Hampshire primary in early January, then wrapped up the nomination on Feb. 5 with big-state primary victories on Super Tuesday.
Obama, campaigning in swing-state Pennsylvania on Thursday, said he wasn't surprised at Palin's criticism of him, and said Democrats intended to focus on her record.
"I think she's got a compelling story, but I assume she wants to be treated the same way that guys want to be treated," he said. "I've been through this 19 months, she's been through it - what - four days so far?"
Obama's campaign announced it had raised roughly $10 million from more than 130,000 donors since Palin delivered her speech Wednesday night.
Outside the hall, police on horseback thwarted plans by anti-war demonstrators to march on the convention hall.
Scattered protesters inside interrupted his speech briefly near the start. He dismissed them, telling the crowd not to be diverted by "ground noise and static."
Not far from the convention center, police rounded up about 200 protesters on a bridge over Interstate 94. Caught up were reporters from several media outlets, including two AP reporters.