Station Way in Buckhurst Hill, Epping, is back in business following months of negotiation with the council providing support and assistance to keep the branch operating.
The branch will be the first to house a Community Information Point providing access to, and information about, local council services.
The Essex scheme was first announced in February and has to date attracted interest from over 150 other local authorities across Britain with many watching events in Essex as a possible model for their own areas.
Leader of Essex County Council Lord Hanningfield, who has been dedicated to re-opening post offices, said: "This is a truly ground breaking and hugely significant development and I am very proud that we in Essex have been able to achieve, with the reopening of this branch, something that our residents feel so strongly about.
"Post offices are at the heart of our communities and they play a vital role to many of our most vulnerable."
"This is exactly what effective local government should be doing. Identifying local needs and priorities and delivering on them for local people. Essex County Council is setting the benchmark in delivering what its residents want.
Station Way was officially opened by Lord Hanningfield who bought stamps from Mr Chavda the sub-postmaster, and who then posted a postcard to Prime Minister Gordon Brown to announce that the branch was open for business.
Mr Chavda has been running Station Way for 11 years and was closed by Post Office Ltd in February this year.
"When we closed a lot of my customers told me how strongly they felt about it and I had a lot of support," he said. "Once word got around that we were re-opening I have had such positive comments from residents it has been really pleasing."