"I love you women," she said as the crowd erupted in cheers and applause, "and I hear your voices."
Romney delivered a speech full of emotion and let the audience in on a man few people know.
"As his partner on this amazing journey, I can tell you Mitt Romney was not handed success. He built it," she said.
The hall erupted in cheers when Romney strolled on stage and shared a hug and kiss with his wife of more than 40 years.
Moments later, it was New Jersey Gov. Chris Christie's turn to speak.
"Leadership matters," declared the keynote speaker. "It's time to end this era of absentee leadership in the Oval Office and send real leaders to the White House."
Republican mockery of President Barack Obama began almost instantly from the podium at a convention postponed once and dogged still by Hurricane Isaac. The Democratic president has "never run a company. He hasn't even run a garage sale or seen the inside of a lemonade stand," declared Reince Priebus, chairman of the Republican Party.
While there was no doubt about Romney's command over the convention, the residue of a heated campaign for the nomination was evident inside the hall.
Texas Rep. Ron Paul, who never won a primary or caucus, drew several dozen delegate votes. Earlier, his supporters chanted and booed after the convention adopted rules they opposed, but were powerless to block, to prevent those votes from being officially registered.
Look for ongoing reports from David Ono at the Republican National Convention in Tampa, Fla. Eyewitness News will also be at the Democratic National Convention in Charlotte, N.C., in September.
The Associated Press contributed to this report.