All the workers at the plant are to keep their jobs, while the new owners plan to take on several hundred more staff.
The site in Belfast has been purchased by InfraStrata, a company that works on energy infrastructure projects.
Infrastrata said it planned to increase the size of the workforce by several hundred over the next five years.
In recent decades the business has moved away from shipbuilding to focus on wind energy and marine engineering projects.
The shipyard, whose giant yellow cranes nicknamed Samson and Goliath dominate the Belfast skyline, is famed for building the Titanic, which sank on her maiden transatlantic voyage in 1912 after striking an iceberg.
“I firmly believe that the shipyard has a promising future and that InfraStrata’s plans present an exciting opportunity for both Belfast and Northern Ireland’s manufacturing and energy sectors.”
Since the business went into administration over the summer, workers have occupied the site in a campaign to secure its future and save their jobs.
Susan Fitzgerald, regional co-ordinating officer with Unite, said: “From 29 July, when workers were faced with the imminent collapse of the yard, they were determined not only to save their own jobs but to safeguard Northern Ireland’s skillbase going forward.
“Their nine-week occupation will be remembered by future generations of workers as evidence of the power of collective action.”
Denise Walker, senior organiser with the GMB union, added: “While politicians substituted sympathy for action, workers took control of the situation and of their workplace.
“In so doing they have ensured that Harland and Wolff will not only continue but will be in a position to expand and fulfil its potential as a lynch pin of Northern Ireland’s economy.”
The company’s employees are now set to be involved in works on InfraStrata’s proposed underground gas storage facility at Islandmagee in Co Antrim.
Mr Wood said: “While our core priority will be to deliver our flagship project in Islandmagee, we believe there are opportunities to welcome potential new clients due to the diverse skill set at the facility.
“This acquisition will clearly provide substantial advantages through vertical integration in addition to demonstrating our commitment to the Northern Irish economy, particularly in the post-Brexit era.”
Credit: Sky News