WASHINGTON, March 12 — D. Kyle Sampson has never worked full time as a federal prosecutor. But for much of the Bush administration he played a considerable role in vetting who served in the Justice Department. And last year he used his post as chief of staff to the attorney general to make a bid for a job as a United States attorney in Utah.
In many ways, until his resignation Monday, the rapid rise of Mr. Sampson, from a low-level aide on the Senate Judiciary Committee to one of the most senior advisers to Attorney General Alberto R. Gonzales, is like that of many other young, ambitious lawyers who come to Washington with a passion for politics.
He arrived in Washington in 1999, around his 30th birthday, with impeccable credentials — at least for a man his age — among religious conservatives. A native of Utah and a Mormon, he had completed his undergraduate studies at Brigham Young University. Mr. Sampson then followed the lead of Dallin H. Oaks, the former president of Brigham Young, by attending the University of Chicago for law school, another bastion of conservatism.
When President Bush was first elected, Mr. Sampson joined his transition team, helping screen nominees for judiciary or Justice Department jobs, said Taylor Oldroyd, a longtime friend. Mr. Sampson had learned about the nomination process from 1999 to 2001, when he worked for Senator Orrin G. Hatch, Republican of Utah, while he was chairman of the Judiciary Committee.
Once Mr. Bush was inaugurated, Mr. Sampson joined the White House staff, helping interview many of the candidates who were applying for jobs as United States attorneys. In 2002 Mr. Sampson told the Brigham Young University news service that he admired Mr. Bush because the president recognized that politics and religious beliefs could not be separated.
“He really means it when he says he believes that we shouldn’t chase religion from the public square,” Mr. Sampson was quoted as saying.
Mr. Sampson also helped fellow Mormons and friends win jobs in the administration, said Mr. Oldroyd, who landed a job at the Agriculture Department in part through Mr. Sampson’s efforts.
By 2003, Mr. Sampson had moved to the Justice Department, where he became an adviser to Attorney General John Ashcroft. When Mr. Gonzales replaced Mr. Ashcroft, Mr. Sampson became one of his senior aides, rising in late 2005 to chief of staff.
Mr. Sampson was better known as a loyal workaholic, rather than for having outstanding legal skills, several people who have worked with him over the years said.
“He is smart, he is loyal and he works hard,” Mr. Oldroyd said.
He was also known as the gatekeeper to Mr. Gonzales, as well as his traveling companion, which resulted in his speaking with United States attorneys from around the nation.
Tasia Scolinos, a Justice Department spokeswoman, said that officials there were saddened by Mr. Sampson’s resignation and that he had been particularly effective on helping define and move ahead on priorities like child exploitation and gun crime.
As his influence rose inside the Justice Department and the White House, Mr. Sampson decided at some point that he wanted to move directly to the post of United States attorney in Utah, his home state, without serving as a full-time prosecutor first.
Paul M. Warner, then the United States attorney in Utah, said Mr. Sampson brought it up at a lunch the two had in Washington.
“Washington is full of young ambitious lawyers,” said Mr. Warner, who stepped down as United States attorney in early 2006 and is now a federal magistrate judge. “Kyle was honest enough, up front enough, to come to me and say, You have the job that I want.”
White House and Justice officials backed Mr. Sampson in his bid to replace Mr. Warner, making that clear to the staff of Senator Hatch. But the senator wanted Mr. Bush to nominate Brett Tolman, a one-time Utah federal prosecutor who had spent the previous three years working on antiterrorism issues for the Judiciary Committee staff.
This put Mr. Sampson in an unusual position. As Mr. Gonzales’s chief of staff, he was fielding calls and letters from Mr. Hatch’s office, even though he was vying for the job that Mr. Hatch was writing about, two former officials from Mr. Hatch’s office said. That made at least some Senate officials uncomfortable.
“It was a little like the fox watching the hen house,” said one former Senate staff member, who asked not to be named because he now works in a different job.
Mr. Sampson did not respond to phone calls seeking comment.
Mr. Hatch finally made a personal appeal to Mr. Gonzales to drop his bid to nominate Mr. Sampson. After a four-month delay, President Bush nominated Mr. Sampson’s rival for the job last June