She added: "It's going to be a challenging time for the school board for the next few months."

Eberhart recalled that in preparing educators for the common core, Santelises brought in the writers of the new standards so that educators could hear about the new curriculum directly from the source.

She overhauled professional development to be more intensive and to have more substance. And she began coaching principals, who are now "instructional leaders" and part of a decision-making team.

Now, Santelises said, it's time for her to advocate for educators at the next level.

"There hasn't been this much activity at the federal level in one to two decades," she said. "And I think the biggest frustration has been this question of: Where is the ground-level voice in the national focus? It's an important time to steer that conversation, and I feel strongly that someone needs to advocate at the national level, to make the road easier for leaders and teachers who put their trust in our team."

Among those leaders was Principal Amanda Rice, who through tears on the first day of school last week recalled how Santelises encouraged her to move to the larger Waverly Elementary/Middle School this year.

"She taught us so much," Rice said. "We're so far ahead, because she set the tone for us."

Rice said that she was persuaded to leave George Washington Elementary — a school she turned around after a cheating scandal — because Santelises had a vision for her personal growth and the system wants to match strong leaders with schools that need them.

"I feel like she's prepared me for this," Rice said. "I'm a little scared, a little humbled. But she gave me my wings, and now I have to fly. We all do."

Sonja Santelises

Age: 46

Family: Married mother of 4-year-old twin daughters and a 7-year-old daughter

Education: bachelor's degree from Brown University; master's in education administration from Columbia University; doctorate of education in administration, planning and social work from Harvard University; completed post-doctoral work at Harvard's urban superintendents doctoral program.

Career highlights: chief academic officer in Baltimore schools, 2010-present; assistant superintendent of pilot schools and assistant superintendent of teaching and learning/professional development in Boston public schools, 2005-2010; part of original staff of Teach for America, where she was director of professional development and teacher placement, 1989-1992.