The new school will be built on land next to the Leckwith Stadium in the Canton area of the city.
Work is expected to be completed in the 2022/2023 Academic Year.
Deputy Leader of Cardiff Council, and Cabinet Member for Education, Employment and Skills, Cllr Sarah Merry, said: “We are looking forward to working with Kier to deliver a brand new school providing pupils with access to state-of-the art facilities and the highest quality learning environment.
“The scheme represents a significant investment in the Canton area and will ensure the local community will also benefit from excellent, modern amenities.”
Anthony Irving, Managing Director, Kier Regional Building Western and Wales said: “We are proud to be working in partnership with Cardiff Council to provide a facility where young people can learn and develop in an inspirational and collaborative environment.
“The new school and sports complex will help shape the futures of young people in Cardiff for years to come and continues our commitment to delivering a legacy within the city where we plan to deliver apprenticeships and training opportunities throughout the project”.