Midland Metro passengers have been barred from travelling beyond the Priestfield stop - nearly two miles from the city's ring road - since the middle of June.
The section of line was closed so tracks could be replaced along the A41 Bilston Road, with the Midland Metro Alliance improving drainage and resurfacing the road at the same time.
It has been a major inconvenience for passengers who were offered a replacement bus service between The Crescent and Wolverhampton Bus Station.
And it has had very serious consequences for businesses along the busy road linking Bilston and the city centre.
That is because for the duration of the works the road was closed to traffic heading into the city.
Two firms - Smoke Busters and The Grafix Workshop - have paid the ultimate price and were forced to close.
Others, such as Coffee Express, have reported huge losses of up to 80 per cent.
Traders have been further angered after being refused compensation for loss of earnings. The Midland Metro Alliance said in September that UK legislation does not allow for compensation for ‘maintenance’ projects.
Instead they vowed to help with "marketing and promotion" and ran an advertising campaign on social media which reached "in excess of 22,000 local people."
There was further fury in October when it was revealed firms in Birmingham were given compensation while the line there was extended to Grand Central and the railway station. The extended line opened in June last year.
It was argued these works were classed differently under national legislation meaning compensation was due to affected businesses.
An action group set up to represent the interests of Bilston Road firms continues to fight for payouts.
Passenger Sue Rock, aged 59, was delighted to be able to use the service into Wolverhampton once more yesterday afternoon.
She said: "I used to park in Bilston and then get the Metro into town. For the last six months I have gone to Birmingham instead to do my shopping as I don't want to drive into town. It is too busy and there is too much faff with parking, it is too much trouble.
"I am so glad it is back on. That is why have come and used it today."
Councillor Wendy Thompson, leader of the Conservative group on Wolverhampton council, said it was relief to have the road and the tram line reopened in time for Christmas.
She said: "Undoubtedly this is very good news. Bilston was far more isolated away from the city centre while this was going on.
"Coming up to Christmas it is really important for all the shops to be that much busier.
"Also for people getting to work it is so much better as this is one of the main arterial routes into and out of the city.
"It is really important everything is back to normal by Christmas."
The works along Bilston Road were completed two weeks ahead of schedule on December 2 and testing has been taking place on the line this week.
Passengers were due to be allowed back on trams from Sunday but that was also brought forward and services began yesterday morning.
There was a traffic lights failure at Ettingshall Road between 9am and 10am which prevented the service from entering Wolverhampton.
Phil Hewitt, Head of Metro Development for Transport for West Midlands said: “This means services have resumed into the heart of the city exactly in time for Christmas.
“These were essential maintenance works that had to be done and I would like to thank the Midland Metro Alliance and their contractors for their hard work in finishing ahead of schedule, and also the public for their patience during the works.”
Tom Stables, Managing Director of National Express West Midlands, which operates the tram, said: “I’m delighted that we can start running a full tram service again - and ahead of schedule.
“It’s great news for our customers travelling to and from Wolverhampton this Christmas time.
“The teams at the Midland Metro and the Midland Metro Alliance have worked very hard together to get the works and testing completed as soon as possible.”