Amid talk of a “clean sweep” of the former White House press spokesman’s close associates – which the White House press office denied – President Bush strode into the press briefing room and said Tony Snow would replace Scott McClellan as his press secretary.

“Tony already knows most of you,” he said. “He agreed to take the job anyway.”

Mr. Snow, 50, a Fox News Radio host, joins a White House in the midst of a shake-up by its new chief of staff, Joshua Bolten. U.S. Trade Representative Rob Portman is expected to head the Office of Management and Budget, the hot seat just vacated by Mr. Bolten, and other personnel changes are expected, from appointing a new secretary of the Treasury to shifts in lower positions.

Reached as he was leaving Fox News Channel’s Capitol Hill studios, Mr. Snow told The New York Sun that he does not expect to make any immediate changes in personnel to the 10-person White House press office. He officially starts work on May 8, but said he will be in the White House today and next week to speed along his transition.

Mr. Snow is expected have an unusual amount of access for a White House press secretary. Like other men in his position, he will be able to walk into the Oval Office to talk to the president. More unusually, it is part of his job description to sit in on high-level discussions that shape Bush administration policy, not simply to strategize on how to spin those policies to the press.

This represents a sharp break from Mr. McClellan, as is his salary, which was reported last year to be $161,000. Mr. Snow will be paid, like all other assistants to the president, roughly $164,000, according to a White House assistant press secretary, Erin Healy.

The invitation to work at the White House, which was proferred on Thursday night, comes as a pleasant surprise for someone who faced an uncertain future when colon cancer carved 40 pounds from his athletic frame two years ago.

After a rigorous regime of chemotherapy, his cancer is in full remission. And his oncologist telephoned him Tuesday night to confirm that he is cancer free, a verdict which cleared the way to his accepting the post.

Well known to his friends as a straight speaker, he is not always known as a straight arrow. When he confided to a friend at a funeral that he had converted to Roman Catholicism, he said, “I’m a mackerel snapper now.” It was just what the somber occasion needed.

He is a regular churchgoer who curses and a keen basketball player in a town that plays golf.

He belongs to a rock band called Beats Working, and he has not been shy about his repeated criticisms of the current administration, though that sense of distance from the president will come to an abrupt end.

The FOX News Radio talk show host spoke for many conservatives when he wrote in November 2005 that Mr. Bush’s “wavering conservatism has become an active concern among Republicans, who wish he would stop cowering under the bed and start fighting back.”

His candor was soon turned against him. No sooner had the president announced that Mr. Snow would be the new press secretary than the Democratic National Committee began broadcasting copies of Mr. Snow’s columns and talk-radio commentary.

One example the Democrats delighted in was a November 11, 2005, comment by Mr. Snow, contending that GOP electoral defeats showed that “George Bush has become something of an embarrassment.”

The record shows that Mr. Snow attacked the White House on issues ranging from government spending to the president’s quirky grasp of grammar.

Mr. Bush acknowledged yesterday that Mr. Snow is no administration parrot. “For those of you who’ve read his columns and listened to his radio show, he sometimes has disagreed with me. I asked him about those comments, and he said, ‘You should have heard what I said about the other guy.'”

As the first working journalist in almost 30 years to take the post – the last was Ron Nessen in the Ford years – Mr. Snow brings rare press experience to the job.

“He brings a long record of accomplishment to this position,” the president said. “He has spent a quarter of a century in the news business. He’s worked in all three major media: print, radio, and television.”

Until yesterday, Mr. Snow hosted a nationally syndicated radio program called “The Tony Snow Show.”

Mr. Snow joined the Fox network in 1996 and hosted “FOX News Sunday” from 1996 to 2003, where he interviewed a number of future administration colleagues, including National Security Adviser Condoleezza Rice and Secretary of Defense Rumsfeld.

Before joining FOX News, Mr. Snow was a nationally syndicated columnist with the Detroit News, from 1993 to 2001. He was also a columnist for USA Today from 1994 to 2000.

In 1991, Mr. Snow took a sabbatical from his job as editorial page editor at The Washington Times to work in the White House for President George H.W. Bush, where he wrote speeches.