Roads Minister Conor Murphy made the announcement on Monday afternoon and the bridge opened on Wednesday, after seven months of closure.
"Completion of the Hightown Bridge has always been a high priority and its opening ahead of programme is good for residents and businesses in the Glengormley and Mallusk area," said Mr Murphy.
He said excellent progress has been made on construction of the bridge over the busy M2 motorway.
The Minister added: "I fully understand the impact that the bridge replacement works have had on local people, particularly those that used the Hightown Road on a regular basis. I would like to thank them for their patience during the construction period."
The old Hightown Bridge was closed in January to allow the structure to be demolished and a new bridge constructed. It was originally expected that this work could take up to one year. However, Roads Service and its contractor, HMC, committed to accelerating the bridge replacement works.
The new Hightown Bridge is wider and has a right turning lane from the Hightown Road into the Mallusk Road, which will improve the capacity of the junction.
South Antrim MLA Mitchel McLaughlin said: "This will relieve the pressure on commuters and will be particularly welcomed by parents whose children have just returned to school this week.
"When the work was first announced I joined with other public representatives to impress on the Minister the serious inconvenience that it would pose to residents and commuters. Minister Murphy undertook to convey these concerns to Roads Service and the contractor and was able to reassure the residents that everything possible would be done to expedite the work. I am glad to see that the Minister's assurances have been delivered on and that motorists will not have to be concerned with this inconvenience in the run-up to Christmas."
Glengormley councillor Nigel Hamilton was Mayor at the time the bridge was closed. He said he is delighted the bridge has reopned but added he will fight for a rates reduction for local businessed affected by its closure.
"I am delighted that the decision to reopen the reconstructed Hightown Bridge has been announced ahead of the schedule.
"I am particularly pleased that the lobbying carried out by the delegation led by myself when I was Mayor has been taken seriously and the issues brought to the Minister and his senior Road Service staff have clearly played an important part in progressing the project at such a pace as to make the new completion date possible," he said.
"A great number of residents in the Hightown and Upper Hightown Road, traders from Glengormley and local schools have all been seriously affected by the major delays visited upon the community by the decision to carry out this work last year.
"The battle is not yet over, I vowed to fight for both residents and traders in terms of reduced rates and I will be seeking a rebate for all those who approach me. I would therefore ask any one interested to contact me through Mossley Mill or directly by mobile of email and I will respond to their request."
Terry O'Boyle, a local taxi proprietor, said he was pleased at the progress made, but frustrated at the manner in which local people had been treated.
"I believe Roads Service and their contractors have learnt a lesson but the people of the Hightown have suffered financially and have been inconvenienced in other ways by the decision to keep them in the dark before this work began. That's why we were so angry.
"I hope that the decision to open the bridge will put an end to this and we can get back to normality."

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