(CNN) -- U.S. Rep. Paul Ryan of Wisconsin is considered a rising GOP star and the Republican Party's leader on fiscal and budgetary issues.
The chairman of the House Budget Committee was first elected to Congress at age 28, and later helped launch the party's "Young Guns" program to recruit candidates in districts where Republicans lost.
Now 42, Ryan is the architect of the House GOP's budget proposal, which Democrats compared to an attack on the poor, but Republicans say is intended to save Medicare and rein in spending.
The chairman of the House Budget Committee was announced as the running mate for presumptive GOP nominee Mitt Romney.
"It's [Romney's] decision months from now, not mine. So why spend my time thinking about it? If this bridge ever comes that I should cross it, then I'll think about it then. It's not the time to think about it," he told The Wall Street Journal in April.
A native of Janesville, Wisconsin, Ryan earned a degree in political science and economics from Miami University in Ohio in 1992. He was raised as a Catholic, and worked at a family construction company before getting into politics. He's known to be an avid hunter and a fitness fanatic.
In the House, Ryan is also a senior member of the Ways and Means Committee.
He has frequently pushed the Republicans' "class warfare" line against President Barack Obama and is a major critic of his signature health reform law.
"If you give us more elected representatives to fix this problem, we will fix this problem in 2013," Ryan said in an interview with CNBC.
Because he hails from Wisconsin, an important battleground, Ryan's youthfulness could appeal to a group with whom the president enjoys advantages.
Ryan is considered a lightning rod, and his presence on the GOP ticket will fundamentally change the 2012 race.
"It would be a bold choice," CNN senior analyst David Gergen said earlier of a Romney-Ryan ticket. "It would be a risky choice."
But there are upsides.
Ryan will likely energize a GOP base often suspicious of Romney, and add youthful vigor to the race with his energetic debates and campaign methods.
Close friends such as former House colleague Mark Green are adamant Ryan would help across the Midwest.
"I think he does get Wisconsin," Green said. "But I think more importantly he gets that sort of blue-collar conservatism that I think is at the heart of the Republican Party."
For months, Romney has tried to frame the race as a referendum on the first Obama term, specifically the president's economic record.
Adding Ryan to the ticket would mean no escaping an onslaught of Democratic criticism that the Republican ticket would "end Medicare as we know it" as Sen. Chuck Schumer of New York is fond of saying.
One ad, by nonprofit political organization Agenda Project, critical of the Ryan budget showed a man pushing an elderly woman in a wheelchair off a cliff, and ended with the tagline: "Is America beautiful without Medicare? Ask Paul Ryan and his friends in Congress."
Ryan calls the attacks demagoguery and says Obama has failed to put forward serious proposals to reform costly entitlement programs.
This is the "bold" debate conservatives pushing Ryan want, but other Republicans worry it could steer the campaign focus away from the president and onto GOP proposals.
Other potential downsides include Ryan is a House member popular in what was once considered a competitive swing district, but he has never run statewide. He also has no foreign policy experience.
In light of the Sarah Palin 2008 pick, some will question whether the House member is ready to be commander-in-chief.
"He is without question one of the stars of the Republican future over the next 10 to 20 years," Gergen said. "Whether he is ready at this moment, only the campaign trail could tell. And he's going to get, I'll tell you, he is going to take a real beating."
Ryan is also a policy wonk, a self-described nerd who cut his teeth working for conservatives Bill Bennett and Jack Kemp. Friends say it would be a mistake to underestimate his ambition, or his competitive streak.
CNN's Phil Gast and John King contributed to this report.