The House Republicans' fiscal blueprint for 2013 would slash federal spending, lower tax rates and substantially overhaul Medicare in an effort to free the nation "from the crushing burden of debt," Ryan wrote in a document outlining the plan.
In a statement from his campaign, Romney lauded the House Budget Committee chairman "for taking a bold step toward putting our nation back on the track to fiscal sanity." He said he and Ryan were of the same mind on cutting taxes and overhauling the tax code.
"As president, I look forward to working with Chairman Ryan and his House Republican colleagues to pass bold reforms that restore America's promise," he said.
The proposed changes to Medicare differ from what Ryan had outlined last year, drawing instead on a proposal he co-authored with Democratic Sen. Ron Wyden of Oregon that would provide future seniors with a fixed amount of money they could use to purchase either a traditional Medicare-like healthcare plan or a privately run option.
Democratic attacks on the Ryan plan have focused on the Medicare overhaul, saying his initial plan would essentially end the entitlement program. On Tuesday, White House communications director Dan Pfeiffer said the new plan "again fails the test of balance, fairness, and shared responsibility."
In Chicago, the Obama reelection campaign put Ryan's and Romney's plans side-by-side, arguing both favor "radical policies" that would hurt the middle class.
"Governor Romney has said he is on the same page as Congressman Ryan, so America's seniors and the middle class should take note of what that means for them," spokesman Ben LaBolt said.
Newt Gingrich, who found himself at odds with Ryan and many in his party when he called his earlier plan "right-wing social engineering," today praised the Wisconsin Republican as "courageous."
"My plan to grow the economy and balance the budget differs in details but shares the same core principles as Ryan's impressive effort," he said. "As president I would work very closely with Chairman Ryan to reform government and balance the budget."
Lisa Mascaro contributed to this report.