BT will consolidate all of the council's existing contracts and associated invoices into one, removing the need to manage multiple accounts.
Hertfordshire County Council will also benefit from improved service levels and a single point of contact for all service related issues.
The council has opted to deploy the BT Assured Service Extra service as part of its long term strategic plan to migrate existing voice and data networks to a converged network infrastructure.
This will ultimately enable the council to roll-out technology services that will benefit public services.
John Alleyne of Hertfordshire County Council, said, "Long-term, we recognise the huge benefits that convergence can deliver - greater mobility and flexibility for our staff, improved customer communications through our contact centre, and vital efficiency savings too.
"This is clearly an ambitious transition plan and we welcome the phased approach that BT is offering."