Updated with Liz Bowie report from school headquarters:
Maryland schools Superintendent Nancy S. Grasmick is stepping down from her post as the nation's longest-serving state education chief.
Grasmick, 72, announced her retirement this afternoon to a large gathering of workers at the state Department of Education office that bears her name. She'll step down June 30.
"I have made a very tough decision to leave," she said. She highlighted the state's accomplishments on its Advanced Placement performance, its preparation for kindergartners and its successful Race to the Top application.
"I am never saying goodbye. We have three more months together. We will prepare for the next journey," she said with her voice breaking.
Staff members hugged her and cried. One employee, Mary Gamble, said, "She is a fabulous visionary leader, a marker for all superintendents across the country."
O'Malley thanked Grasmick in a statement this afternoon.
"From her days teaching deaf children in Baltimore City, to now serving as the head of America's number one public school system, Dr. Grasmick has been long-regarded as a champion for many of the progressive reforms we've implemented in Maryland," the governor said.
Lawmakers this afternoon praised Grasmick's legacy.
"She's had a great run," Senate President Thomas V. Mike Miller said. "Maryland schools "have a great track record, and it's largely because of her efforts."
Miller said "no one has done more" for K-12 education than Grasmick.
Lawmakers said the next superintendent -- to be chosen by the governor-appointed State Board of Education -- has big shoes to fill.
Sen. Joan Carter Conway, chairwoman of the Senate education committee, called Grasmick "an icon in education" and "an expert in her field."
"She has done the state well," the Baltimore Democrat said.
Sen. Roy Dyson, vice-chairman of the education committee, added: "She can be so proud of what she has accomplished."
Conway said the news does not come as a complete surprise, given Grasmick's sometimes rocky relationship with O'Malley.
"Much like myself, she can be a little controversial, politically," Conway said. She said O'Malley "has always wanted to appoint someone to that position."
Grasmick and O'Malley butted heads as he began his first term in 2007. The Democratic governor joined Miller and House Speaker Michael E. Busch in urging her to step down. The state school board, whose members were chosen by Republican former Gov. Robert L. Ehrlich Jr., reappointed her to a four-year term.
Earlier, as mayor of Baltimore, O'Malley had feuded with Grasmick over an attempted state takeover of 11 failing city schools. And more recently, the two had a difference of opinion over when the state should apply for federal Race to the Top education funds. The state applied in the second round and won.
The news of Grasmick's decision was first reported Wednesday by Fox 45 in Baltimore.