Patrick Fitzgerald, the 47-year old Justice Department wunderkind, has taken on corrupt government, terrorists and the mob. And he's always gotten his man -- at least, so far.

Known to his friends as Fitzy and once named one of the sexiest men alive, he is the Justice Department's knight in shining armor.

Now he has Rod Blagojevich in his sights, having capped a three-year investigation with the arrest Tuesday morning  of the Illinois governor and his chief of staff. It brought to light what Fitzgerald called "a political corruption crime spree" that brought Illinois politics "to a truly new low."

If convicted, Blagojevich will become just one more high-profile name to be brought down by Fitzgerald.

Shortly after he was appointed U.S. attorney for the Northern District of Illinois in 2001, Fitzgerald launched an investigation that put Illinois' previous governor, George Ryan, in jail for corruption.

In 2003 he was named special counsel to investigate the leak of the name of covert CIA employee Valerie Plame, leading to the conviction of Vice President Dick Cheney's chief of staff, I. Lewis "Scooter" Libby, on perjury and obstruction of justice charges two years later.

Before his appointment in Chicago, Fitzgerald spent 13 years as an assistant U.S. attorney in the Southern District of New York, where he helped prosecute the 1993 World Trade Center bombers and four terrorists convicted of bombing U.S. embassies in Kenya and Tanzania in 1998.

He gained the reputation of a tough and relentless workaholic who was always on the job. According to a 2002 profile in Chicago Magazine, he didn't even bother to turn on the gas in his Brooklyn, N.Y., condo because he never went home.

He did, however, take a break this year to marry 34-year-old Chicago schoolteacher Jennifer Letzkus.

"In some of these stories he reaches legendary status," said Patrick Collins, a former assistant U.S. attorney for the Northern District of Illinois who worked with Fitzgerald from 2001 to 2007.

"He came to us right around 9/11 with a reputation as a hands-on prosecutor's prosecutor, not someone who sat in his office and waited for people to come to him," Collins said. "For someone who was running an investigation, he struck a great balance on being supportive, in a way that's not meddling, in a way that was productive."

Collins said Fitzgerald has a buttoned-up personality in public -- "very controlled and under control" -- but off-camera he's just a regular guy.

"In the calm of the office, in the occasional social gatherings that I had with him, he's very engaging; he's got a great sense of humor. The Sexiest Man Alive thing was a big joke in the office," he said.

People magazine named the Brooklyn-born Fitzgerald to its list of sexiest people in 2005.

But not everyone is riding the Patrick Fitzgerald love train. Critics called him overzealous in the wake of his prosecution of Libby. During the investigation, he threatened to put two reporters in jail for not saying who revealed Plame's CIA status to them.

Judith Miller, a FOX News contributor who at the time worked for the New York Times, refused to reveal her source and spent 85 days in jail.

Matthew Cooper, a former Time magazine reporter, revealed his source after the source gave him the green light. This week in a blog post called "Dear Governor Blagojevich," he warned the governor about the prosecutor, calling Fitzgerald a "hard ass, but a reasonable one" and "notoriously single minded."

Cooper wrote: "He's married now, but I'm sure the son of Irish immigrants is still a workaholic, and having convicted what seems like half of Chicago (along with the likes of Scooter Libby and Conrad Black), I don't think he's slacking off just because a new president is coming in. I'm sure you know about how tough he is."

"I don't think Fitzgerald is a cruel man," Cooper continued. "He could have put my big white butt in jail as soon as the first federal judge laughed my case out of court. But he didn't. He waited for me to make all my appeals to the Supreme Court, which meant putting his incredibly high-profile case on hold for a year. A vengeful prosecutor wouldn't have done that."

Washington lawyer Victoria Toensing said she believes Fitzgerald is overzealous. In a Washington Post op-ed in 2005, she wrote about the prosecution of Libby and questioned whether leaking Plame's name was even against the law.

"He didn't have a crime and he pursued it," Toensing said of Fitzgerald. "He doesn't know the color gray, he's only black or white, and just about everyone but him does wrong."

She said Fitzgerald crossed the line this week when he gave his opinion on the Blagojevich case at the Tuesday press conference announcing the governor's arrest.

"He did so with Scooter and he repeats it again," Toensing said. "The rules are the prosecutor is not supposed to talk outside of the four corners of the indictment, and a line like 'Lincoln would turn over in his grave' is outside the ethics of a prosecutor.

"You're not supposed to be talking beyond what's in the indictment. He's supposed to abide by those rules," she said.

"He uses his power and the press laps it up, but he abuses his power. I am appalled too at what Blagojevich did, but that's not for [Fitzgerald] to be able to say. That's for the rest of us."