Formerly part of the Kent Building Schools for the Future programme, the project will see construction at two sites on the east and west of the island, to serve 2,450 students.
The Academy, specialising in business, enterprise and sport, will include a media suite, drama facilities, dance studios, performance studio, sports halls and outdoor sporting facilities.
It will be built with several renewable energy measure to reduce emissions by 60% compared with 2002 building regulation standards.
Kier Group chief executive Paul Sheffield said: “As a company committed to providing first class learning establishments for the 21st century, Kier is particularly proud to be involved with the delivery of this landmark scheme.”
Construction work on both sites in Sheppey has just started with completion due by August 2013.