At a campaign appearance in his home state of Michigan Friday, the former Massachusetts governor spoke of having grown up in the state with his wife, Ann.
"I love being home in this place where Ann and I were raised, where both of us were born. Ann was born in Henry Ford Hospital. I was born in Harper Hospital," Romney said in Commerce. "No one's ever asked to see my birth certificate. They know that this is the place that we were born and raised."
The remark -- a play on a controversy stoked by Obama's political opponents even though the president has released his long-form Hawaii birth certificate -- drew a laugh from Romney's audience and a rebuke from President Barack Obama's re-election campaign.
"Throughout this campaign, Governor Romney has embraced the most strident voices in his party instead of standing up to them," Obama campaign spokesman Ben LaBolt emailed reporters. "It's one thing to give the stage in Tampa to Donald Trump, [Arizona] Sheriff [Joe] Arpaio, and [Kansas Secretary of State] Kris Kobach. But Governor Romney's decision to directly enlist himself in the birther movement should give pause to any rational voter across America."
Romney told CBS News Friday he had intended the comment as a joke.
"No, no, not a swipe," Romney said. "I've said throughout the campaign and before, there's no question about where he was born. He was born in the U.S. This was fun about us, and coming home. And humor, you know -- we've got to have a little humor in a campaign."
In a commentary published in Friday's Wall Street Journal, Romney said his time running Bain Capital taught him how to create a positive business environment.
"When you see a problem, run toward it before the problem gets worse," Romney wrote.
The lessons he learned during his 15 years at Bain were "valuable" in helping turn around the 2002 Winter Olympics in Salt Lake City and in turning a budget deficit into a surplus while lowering unemployment when he was governor of Massachusetts, Romney said.
"The lessons from that time would help me as president to fix our economy, create jobs and get things done in Washington," Romney said.
A Romney presidency would make it easier for entrepreneurs and small businesses to get investment capital they need to expand by reducing and simplifying taxes, scrapping the Affordable Care Act and by "stemming the flood of new regulations that are tying small businesses in knots," he wrote.
"I am committed to capping federal spending below 20 percent of GDP [gross domestic product] and reducing non-defense discretionary spending by 5 percent," Romney said in the op-ed piece. "This will surely result in much wailing and gnashing of teeth in Washington. But a failure of leadership has created our debt crisis, and ducking responsibility will only cripple the economy and smother opportunity for our children and grandchildren."
President Barack Obama has instituted excessive regulations, proposed massive tax increases, added to the federal debt and "failed to address the coming fiscal cliff," miring the country in "sluggish growth and high unemployment," Romney said.
"I know what it takes to turn around difficult situations," he said. "And I will put that experience to work to get our economy back on track, create jobs, strengthen the middle class and lay the groundwork for America's increased competitiveness in the world."