Antonio Burt, who was hired to lead an aggressive effort to turn around eight of Pinellas County's lowest-performing schools, has resigned and will leave at the end of June.Burt has been on the job for about a year and a half and was the first director of the school district's new Transformation Zone. He built a reputation as a "turnaround leader" after improving struggling schools in Memphis. Superintendent Mike Grego said Friday that he was grateful to Burt for his work in Pinellas and credited him with creating a stronger foundation in the eight schools in the zone. "We as a district learned a lot," he said.Burt couldn't be reached for comment Friday, but Grego said Burt's reasons for leaving were personal. Burt got married last fall; his wife works in Memphis. Burt has offered to return as a consultant as needed to help with the transition, Grego said."The work's not done. He knows it. I know it," he said. "But … we've made great progress this year."Burt, who reported directly to Grego, stepped into the high-profile role in December 2015. His job was to oversee the improvement of five struggling St. Petersburg elementary schools — Campbell Park, Fairmount Park, Lakewood, Maximo and Melrose — that were dealing with the effects of racial and economic segregation. Later, Grego added three other schools: Sandy Lane and High Point elementary schools, both in Clearwater, and Midtown Academy in St. Petersburg. Three of the original five schools improved their school grades last year; Maximo jumped to a C from an F, while Lakewood and Fairmount Park earned D's.In his resignation letter, Burt said he has "full confidence" that his replacement will be able to build on the momentum.Burt introduced a new assessment, the Measures of Academic Progress, or MAP, which is used in school districts nationwide, to provide teachers and principals with data more closely aligned to the Florida Standards Assessments. All elementary schools in the district will use it next year. The zone's leadership team also created biweekly assessments in an effort to provide teachers with data faster.This was the first full school year of Burt's leadership, and it's still unclear how well the eight schools will do on the state's standardized exams. Some students still are taking the tests. District officials said in March that they were seeing promising signs in the schools. The D-rated High Point had the highest performance and growth on internal tests. Melrose, an F school, also had "high levels" of growth in reading and math. Maximo, which jumped to a C, had continued to make "impressive" strides, they said.Grego said he plans to advertise Burt's job and will give the School Board an update about the Transformation Zone later this month. Board member Linda Lerner said she believes the district will get someone good to take over."I have every reason to believe he's done a good job," she said.Maria Scruggs, president of the St. Petersburg branch of the NAACP, had previously expressed concerns about how Burt's position meshed with the creation of another new district position, the minority achievement officer. She said she was happy for Burt, but: "I just wonder if we're going to see the results."Contact Cara Fitzpatrick at [email protected] or (727) 893-8846. Follow @Fitz_ly.