The Chalkdene Developments partnership will provide new homes and jobs across the county through a series of housing-led developments on the council’s surplus land.
The deal is for 15 years with the option to extend to a further five.
The partnership will initially focus on 12 locations with up to 40 in the eventual pipeline with a gross development value of up to £2bn.
Chalkdene will work with Morgan Sindall’s partnership homes developer Lovell and its construction and infrastructure divisions.
John Morgan, Chief Executive of Morgan Sindall Group, said: “This win demonstrates the potential for our Investments division to become a meaningful contributor to Group profits.
“It also reflects our ability to leverage our diversified portfolio of businesses to offer our partners and customers a comprehensive solution spanning strategic partnerships and project delivery.
“We understand how important the development of new housing is for Hertfordshire and are excited to have the opportunity to work with Herts Living in achieving the Council’s vision.”
Steve Faber, managing director of Herts Living, said: “We are delighted to be working with Morgan Sindall Investments to deliver new, high quality, sustainable houses that will help the county to meet the needs of its growing population, reduce the housing shortage and provide much needed social housing and community assets.
“Doing this will also release significant capital over the long term for strategic expenditure and investment.”