The appointment takes effect Saturday.
Korostoff is currently assistant superintendent for curriculum and instruction, overseeing the K-12 academic program, and will continue in that role in the immediate term. He has worked for the school district since 1998.
Organisciak, who has served as the district’s superintendent of schools for the last seven years, announced his retirement earlier this year.
He originally planned to retire first at the end of the school year and then at the end of October, but his reportedly deteriorating health moved up the time of his departure.
A nationwide search for a permanent superintendent is under way.
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