Problems at the shipyard arose following a dispute over who should pay for £130m of extra work on two oil drilling ships ordered by the Texan company Global Marine.
As negotiations got under way with the US firm and the yard's financial backers, a political campaign was mounted to save Harland and Wolff, led by senior unionist politicians.
It has now emerged that this campaign at one point involved former US senator George Mitchell, who has been chairing crucial talks on Northern Ireland's political future.
It is not known how important the political pressure was but the shipyard has now said it has reached an agreement with Global Marine which should secure its immediate future.
In a joint statement this morning Harland and Wolff, Global Marine and the shipyard unions said a deal had been struck to complete the two drill ships at the centre of the dispute.
The statement says that all parties will now work together to ensure the timely and efficient completion of the vessels.
BBC NI's Business Editor James Kerr said the agreement, thought to be worth more than £50m to the yard, would give the company breathing space while it attempted to look for new work to fill its empty order book.
"Securing the long term future of the yard will only be achieved by winning more orders," he said.
The dispute over the £130m claim for extra work will be settled by separate negotiation or by arbitration.
The joint statement issued by Harland and Wolff acknowledges the role played by the campaign in support of the shipyard.
It says: "All parties would also wish to express our gratitude to the broad range of individuals and organisations which have played a positive and constructive role in reaching this agreement, including our local politicians from all sections of the community, who have joined together to support us at this very important time."
Mr Mitchell's role in helping to broker an agreement was revealed by the Ulster Unionist Party talks negotiator Sir Reg Empey.
He said it was impossible to say if the talks chairman had made a difference but there was great relief to hear that some agreement had now been found.