Jean-Claude Brizard, a former administrator in New York City, will be leading the country's third-largest district.
Deasy is working on an performance management plan for the district that aims for a higher graduation rate and improved math scores for middle school students, among other improvements.
The Atlanta district's high schools have been put on probation because of school board in-fighting.
The state would like to see principals evaluated more frequently, and create alternate paths to the principalship.
The district is facing school closures and leadership upheaval.
New York observers say the chancellor's dismissal after less than 100 days in office is a sign of mayoral missteps.
Deputy Mayor Dennis Walcott is the mayor's pick to step into the role.
Both were profiled in a recent Education Week article about tea party conservatives flexing their muscle in school board races.
Cathleen P. Black's poll numbers have remained consistently low, but parents of children in the district say they're generally happy with their schools.
The finalists this year have all been nominated for the award before.