The council has a plan, called SG1, to develop a new quarter on the western side of Stevenage town centre. SG1 has a gross development value of around £350m.
The mixed-use scheme includes plans for new streets and a revamped Town Square, as well as housing, shops, restaurants and leisure facilities.
Work is expected to take place over several phases with the first construction project starting in 2020.
David Grover, Mace’s chief operating officer for development, said: “This agreement marks a major step forward for the transformation of Stevenage town centre. With a contract agreed we can now get started in earnest in delivering the regeneration of the town centre - I look forward to seeing our exciting plans come to life.”
Stevenage Borough Council leader Sharon Taylor said: “Signing this deal with Mace highlights our ambitious vision for Stevenage as we grow our town and improve the services, environment and facilities we currently offer to residents. We’ve seen a number of projects already completed in our town centre as part of the regeneration programme including Market Place, Vista Tower and updating of our public spaces. SG1 will be transformational, and drive significant, positive change for our town centre. We’re delighted to have Mace on board and can’t wait for development to get underway.”