United Federation of Teachers Vice President Leo Casey at a public hearing about Opportunity Charter School's charter renewal in November.

A top United Federation of Teachers official who has been the union’s leading intellectual voice in recent years is heading south.

But he won’t be going as far as Florida, a common destination for union members who retire. Instead, Leo Casey, the vice president of academic high schools since 2007, said today that is taking a new position this fall as the director of the Albert Shanker Institute in Washington, D.C. The institute is a research arm of the American Federation of Teachers, the national union to which the UFT belongs.

In his role at the UFT, Casey has been both an intellectual and a seasoned activist. He has represented the union on various panels, forums, and debates on education policy and blogged prolifically for the union’s news and opinion site, Edwize. But he has been just as comfortable protesting at public hearings, where he was known to deliver fiery speeches against school closures, co-locations, and other policies that the union opposed.

In moving to the Albert Shanker Institute, a progressive think tank focused on education and labor policies, he will focus on research. Casey, a city teacher for 27 years, said that he hoped his legacy at the UFT would be of pushing against school reform that is driven by non-educators.

“I think one of the most important things that has driven my time at the UFT is to provide a voice for classroom teachers and that far too much of education policy making today is in the hands of folks who don’t understand what it’s like to teach,” Casey said.

AFT President Randi Weingarten, a close friend and former colleague who helped hire him as a board member on the Shanker Institute, called Casey “an exquisite choice.”

“I could not be more pleased that someone who has been a teacher and a union activist and a leader in the UFT all these years would agree to take over this very important think tank,” said Weingarten, who worked and co-taught with Casey when she was president of the UFT.

People who have worked closely with Casey over the years said today that his departure would leave a major hole in the union and that he would be difficult to replace.

“Leo’s very, very bright. He’s very much a public intellectual,” said education historian and activist Diane Ravitch, who sits on the Shanker Institute’s board.  “I think there should be somebody who can kind of be the intellectual and policy face of the union.”

Casey has also been one of the UFT’s staunchest defenders. In February, Casey used Edwize to take on Ravitch and Carol Burris after they criticized the union for endorsing a teacher evaluation deal that they believed counted test scores too heavily. Casey challenged their grasp of the complex issue and believe their public writings on the subject were misguided.

“Unfortunately, complexity has provided a fertile ground for commentaries on the New York teacher evaluation framework that reach alarmist conclusions, with arguments built on a foundation of misinformation and groundless speculation,” he wrote.

Casey also butted heads with activists who were traditionally aligned with the union. At a Panel for Educational Policy meeting earlier this year, Casey drew heat from Occupy the DOE protesters who wanted the union to join them in a united rally.

Yet even traditional enemies of the union said they respected him.

“This is a big loss for the UFT,” said Gideon Stein, a vice chair of Success Academy Charter Schools. “Leo is their leading intellectual and probably best writer.”

Stein, president of Future is Now Schools, was also on the other side of the negotiating table when Green Dot Charter High School teachers recently signed an updated union contract.

“I really liked working with Leo and while we certainly have don’t see eye to eye on a lot of issues, he’s a very decent guy,” Stein added.

Casey currently teaches global studies at Manhattan’s Bard High School Early College. Previously, he taught at Clara Barton High School, including a stint when he co-taught with Weingarten.

“For me, it’s all the same movement,” Casey said of his decision to leave the UFT. “It’s the same purpose. I’m just doing it in a different place.”

He added, “I have something important to add on the policy side and to really speak with some authority. I think in some ways it’s a job that I am particularly well-prepared for.”

Below: Watch a video of Casey arguing with Brian Jones, a teacher who is active in the Grassroots Education Movement, about protest tactics for a PEP meeting where school closures were on the table.