Maryland school superintendent Nancy Grasmick announced her retirement this afternoon at the State Department of Education’s headquarters.  She will step down June 30, a year before her contract expires.

Grasmick, the longest-serving school chief in the country, has served as state superintendent for two decades. Since her arrival, the Maryland school system has won numerous national awards, including the nation’s best school system award from Education Week three years in a row.

“Our students and our schools have made tremendous progress over the past two decades, and stand on the edge of even greater progress,” Grasmick said in a press release.  “It has been my great honor and privilege to work with our state’s outstanding educators to provide our children with the educational system they richly deserve.”

Governor O’Malley thanked Grasmick for her work as state superintendent of schools, setting aside their past disputes over education policy.

“From her days teaching deaf children in Baltimore City to now serving as the head of America’s No. 1 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 in a press release.

Grasmick told the Associated Press she wanted more flexibility in her life, but didn’t comment on the specific reasons for her departure.