The firm was selected by Enfield Council beating rival shortlisted bids from L&Q, Peabody and Redrow.
This first phase includes a high proportion of affordable homes alongside new public squares, shops and leisure facilities and will be located around the new Meridian Water train station.
The first new homes are expected to be available in 2022.
Stephen Teagle, Chief Executive of Galliford Try Partnerships, said: “We are delighted to have been selected to work in close partnership with Enfield Council and the local communities on the delivery of Meridian One as a new, vibrant mixed-use, mixed tenure neighbourhood.
“We will provide high quality affordable homes, opportunities for local start-up businesses to flourish and great public spaces.
“It’s a great opportunity to demonstrate responsible and accountable regeneration through a responsible, accountable partnership.“
Enfield Council has now started the bidding race for phase two of the scheme.
Meridian Water will regenerate 85 hectares of land creating a new district in London containing 10,000 homes, schools, health facilities, rail infrastructure and new open spaces.