Josh Wallack, the education department’s top strategist, has been promoted to deputy chancellor and is taking on an expanded leadership role as the city’s school-support structure begins to change, Chancellor Carmen Fariña announced Friday.

Wallack’s new title, deputy chancellor of strategy and policy, comes with oversight of the office of enrollment, which handles admissions and placement for the school system’s 1 million students each year. He will also take over management of seven new support centers opening this summer, which will replace the current system of school-support networks and help schools with every part of their work, from hiring and training staffers to handling safety issues.

Fariña also appointed Elizabeth Rose to deputy chancellor of operations, a position Rose had filled on an interim basis since Kathleen Grimm stepped down in January after 13 years.

“These thoughtful, dedicated individuals have shown their value to our schools and City – whether it’s giving students high-quality facilities and meals that help them thrive in the classroom, or leading the charge to offer pre-K to every four-year-old across the City,” Fariña said in a statement on Friday. “These are integral leaders and I’m thrilled to have them serve in this new capacity.”

Wallack’s previous title was chief strategy officer, a position created when he joined the department in March 2014. He will continue to oversee the department’s pre-kindergarten expansion, Mayor Bill de Blasio’s signature education initiative.

Unlike many of Fariña’s high-level appointments, Wallack has no teaching experience, which Fariña has said before is an important qualification for members of her leadership team. But Wallack was central to planning the school-support reorganization and has close ties to City Hall, having served as de Blasio’s legislative director in the city council and as Deputy Mayor Richard Buery’s early childhood director when they were both at the Children’s Aid Society.

Wallack’s appointment will lighten the workloads of both Rose, who is ceding control over the enrollment office, and Senior Deputy Chancellor Dorita Gibson, who as Fariña’s second-in-command previously had authority over the school-support work. Gibson will remain in charge of the newly empowered school superintendents, who will work closely with the support centers that Wallack now oversees, a department official sad.

The appointments indicate that Fariña’s inner circle of advisors is expanding. Her leadership cabinet had consisted of four deputy chancellors last year, but it is now up to six following the promotion of English language learner czar Milady Baez in February, the same number she inherited from former Chancellor Dennis Walcott.

The top-level restructuring comes as City Hall is undergoing its own personnel changes. A string of senior staffers for de Blasio have left in recent months.