The U.S. attorney in Manhattan has spent the spring bringing down a governor and exposing dishonesty at the City Council. When Michael Garcia leaves the post, as could happen by year’s end, job offers will likely be forthcoming from the private sector. Mr. Garcia will also surely be encouraged to run for office.

“If the guy’s interested in political life,” the chairman of the state Republican Party, Joseph Mondello, told The New York Sun, “we certainly need all the people with the fire in their belly we can find.”

Not many U.S. attorneys in Manhattan have used the post as a jumping-off point for elective office. The exceptions, however, are noteworthy: Mayor Giuliani, District Attorney Robert Morgenthau, and Governor Dewey.

Mr. Garcia, 46, who as of 2007 was registered as a Republican, grew up in Nassau County and lives in Westchester. He has not yet tested the local political waters.

“If he decided he did have political ambitions, he’d be one of those guys who would do very well,” Mr. Garcia’s onetime supervisor at the U.S. attorney’s office, Andrew McCarthy, said. Mr. McCarthy said he has not spoken to Mr. Garcia about his career plans.

Although he has spent most of his federal career near Foley Square, adjacent to City Hall, Mr. Garcia has stayed largely aloof from city and state political circles, preferring the company of current and former federal law enforcement officials. He is married to an FBI agent.

“He’s unknown in New York City political circles,” the president of New York Civic, Henry Stern, said.

One example: The president of the Bronx, Adolfo Carrion, says he has never met Mr. Garcia, even though the latter has jurisdiction over federal crimes committed in the Bronx.

Nor has Mr. Garcia been particularly active in local bar associations, whose members would be a natural source of campaign funds should he seek office. Mr. Garcia, of Italian and Spanish ancestry, has been honored by the Hispanic National Bar Association.

Mr. Garcia’s only employment in state government came more than 16 years ago, when he clerked for Chief Judge Judith Kaye of the state’s Court of Appeals, who was then an associate judge. From the clerkship, Mr. Garcia joined the office he now heads. He spent much of the 1990s prosecuting and investigating Islamic terrorism. He helped prosecute cases based on the 1993 bombing of the World Trade Center and a plot to blow up airplanes flying to America from Asia. He also worked on the prosecution and the unsuccessful death penalty proceedings of terrorists involved with the bombings of American embassies in Tanzania and Kenya.

Mr. Garcia’s stature in the federal government rose during President Bush’s first term, which Mr. Garcia spent mostly in Washington, D.C. He served as an assistant secretary for homeland security, overseeing immigration and customs matters and a workforce of 20,000 federal employees.

He returned to New York in 2005 as U.S. attorney for the Southern District and quickly faced several high-profile setbacks. A federal judge in 2006 said prosecutors in the office had violated the Constitution by pressuring KPMG to cut off legal fees for employees who were indicted following a major tax fraud investigation. Many white collar defense attorneys saw the office’s tactics in that case as an abuse of prosecutorial power.

In the last year and a half, Mr. Garcia has made a name for himself chasing public officials. In that time, he has indicted a state senator, a state assemblyman, and a former New York City police commissioner; caught Governor Spitzer on a wiretap arranging a liaison with a prostitute, and investigated the City Council for allocating money to nonexistent nonprofit organizations. Only one of those cases so far — the indictment of the assemblyman and labor leader, Brian McLaughlin — has yet resulted in a criminal conviction.

Despite the streak of major cases, some former colleagues say Mr. Garcia appears to seek less press attention now as U.S. attorney than he did while serving as a top immigration official.

“He’s appropriately understated,” Mr. McCarthy, who is now with the Foundation for Defense of Democracies, said. “There’s not a press conference every five minutes; he’s not one of these ‘me me me me’ guys.”

“By this time Rudolph Giuliani had a much higher profile,” a political consultant, George Arzt, said, comparing the former mayor’s tenure as U.S. attorney with Mr. Garcia’s.

Mr. Arzt dismissed the idea of Mr. Garcia having much of a future in New York politics.

“There’s not much for a Republican in New York and nobody knows him,” Mr. Arzt said.

Several people who know Mr. Garcia, but have not spoken with him about his career plans recently, said they expect Mr. Garcia will take a job in the private sector, although not necessarily with a law firm. He is not expected to be nominated for a federal judgeship and there is no indication he has sought one.

“He loves public office and it wouldn’t surprise me if took a job in public service,” a former colleague of his who is still acquainted with Mr. Garcia said. “I think he’d be a great governor. I just don’t know if he’d run.”

Should the next president decide to replace Mr. Garcia with another U.S. attorney, it would likely take several months for a replacement to be confirmed, meaning Mr. Garcia could conceivably be in his post for more than another year. The latest speculation among lawyers and Justice Department sources holds that Mr. Garcia will step down by the end of the year to allow the office’s no. 2 official, Lev Dassin, a chance at the top job. Mr. Dassin is held in high regard by Attorney General Mukasey. While a federal judge in Manhattan, Mr. Mukasey picked Mr. Dassin to co-teach a class with him at Columbia, an arrangement that lasted eight years.