The plans break new ground as the first free school and sixth form college run by a university.
The University of Birmingham is building its own secondary school to help city children from all backgrounds into top institutions.
As tipped by the Enquirer last month, Willmott Dixon beat rival Galliford Try to take the project, which will be built on Weoley Park Road in Selly Oak.
It will accommodate 750 pupils aged between 11-16, with a further 400 places in the sixth form.
Designed by Associated Architects, each school year will have their own teaching cluster grouped around a three-storey central atrium that will house the dining area and provide access to the physical activity and group gathering spaces.
Willmott Dixon will also refurbish an adjacent building to provide additional space for the sixth form.
Construction of the new building will be completed in time for the start of the 2015 academic year in September.
As a University Training School, the University of Birmingham School will provide initial teacher training, ongoing teacher education and research into improving educational practice.
Matthew Raybould, operations director at Willmott Dixon, said: “Willmott Dixon has a strong track record for education across the West Midlands including building the Birmingham City University’s award-winning Parkside Building.
“We are currently engaged in the construction of BCU’s £63 million Curzon Building, which is due to be completed in summer 2015.”