Margaret Spellings, who was named yesterday as secretary of education, arrived in Washington from Texas four years ago as a divorced single mother and member of the palace guard around President Bush.

"She is a multitasker," says Republican political consultant Mary Matalin, who worked out with Spellings in the White House gym, explaining how her friend survived the grueling 12-hour days while juggling her responsibilities to two young children.

"She is very practical and full of common sense," said Austin lawyer Sandy Kress, who worked with Spellings at the White House drafting the No Child Left Behind Act, which aims to introduce business-style accountability in the nation's schools. "She has known the president for so long that she can talk straight to him and have fun with him. She tells him exactly the way it is."

As Bush's senior domestic policy adviser, Spellings has wielded power over the past four years extending far beyond her long-standing interest in public education. She is one of a small group of aides who arrived with him from Texas and appear to enjoy his complete confidence. But for all her behind-the-scenes influence, she is relatively unknown to the public and is rarely quoted in the media.

"I don't like to be in the limelight," she once told a reporter. "I like to be under the radar."

That is likely to change now that Bush has nominated Spellings, 46, to succeed former Houston schools superintendent Roderick R. Paige as the nation's eighth secretary of education. The appointment puts her on the front lines of the national education debate, defending one of the administration's signature domestic policy initiatives against critics who say it is underfunded, overly bureaucratic and likely to lead to many schools being dubbed failures.

Yesterday, Spellings choked up with emotion as she spoke of her commitment to public education. Bush, who is said to regard her as family, put his hand gently on her back. "She's a tough babe, but it's very moving to have that level of trust and confidence bestowed on you by the president," Matalin said.

Spellings's ties to Bush go back to the late 1980s, when he was first considering a run for governor of Texas and she was a lobbyist for the state school boards association. They were introduced by his political adviser, Karl Rove, who felt Bush needed some coaching on educational issues. Bush was so impressed that he asked Spellings to become political director of his campaign when he ran for Texas governor in 1994.

During the Roosevelt Room nomination ceremony yesterday, Rove recalled that he had once asked Spellings out on a date in the early 1980s when they were both single but she had turned him down "brutally."

"It has taken my ego decades to recover," he joked.

Although Spellings is often described as a Texan, she was actually born in Michigan, moving with her family to Houston when she was in third grade. She was smart and precocious, describing herself as "a little Martha Stewart" in high school, inviting her friends to dinner parties. She also had a well-developed sense of humor, donning a theatrical black cape after being described as "a princess of darkness" by a rival lobbyist.

"She was a worthy adversary," said Jay Levin, a lobbyist for the Texas State Teachers Association. "I admired her because of her tenacity and the intensity she brought to debating the issues."

As Bush's educational adviser in Texas, Spellings was responsible for overseeing many of the accountability reforms that later served as a model for the No Child Left Behind legislation. She was involved in a campaign to end "social promotion" by ordering schools to bar third-graders from moving up to fourth grade if they were unable to meet state reading standards.

Some conservatives, such as Reagan education secretary William J. Bennett, have expressed disappointment at her appointment, on the grounds that she is too pragmatic and insufficiently committed to such ideas as school choice. "The emphasis will be on standards and accountability rather than choice-based reform," said Frederick M. Hess, an education expert at the American Enterprise Institute.

Spellings became the subject of conservative sniping soon after moving to Washington after she was asked on C-SPAN to react to census data showing a decline in the traditional family. "So what?" she replied, noting that there were "lots of different types of family" and that she herself was "a single mom."

During her early weeks at the White House, Spellings commuted to Austin on weekends so she could see her children, Mary and Grace, then ages 13 and 8, who remained at school in Texas, living with their father. She later enrolled them at public schools in Fairfax County but moved her older daughter to a Catholic parochial school.

In a 2001 interview with the Dallas Morning News, Spellings described herself as "an earth-mother type of Republican."

After divorcing her first husband in 1997, Spellings remarried in 2001 to Robert Spellings, an Austin lawyer who lobbied in Texas on behalf of the promotion of school vouchers.

Margaret Spellings, President Bush's nominee for education secretary, motions for the audience to hold its applause at a White House ceremony.