Liberty Steel's plant in Rotherham will reopen after a £50 million cash injection into the company.
The money will safeguard hundreds of jobs and is part of a wider restructure of Liberty's owner GFG Alliance, which was forced to seek funding when its key lender Greensil Capital collapsed.
A £50 million cash injection is being made by Liberty Steel, which will safeguard hundreds of jobs in the UK.
The site at Rotherham has been closed since the spring.
Jeffrey S Stein, chief restructuring officer, said: "I'm pleased to report a significant advance in GFG Alliance's global restructuring.
"The debt restructuring we have agreed for Liberty Primary Metals Australia gives the business clarity and stability and secures a clear recovery plan for creditors.
"The funding we are injecting to Liberty Steel UK puts it in a strong position for business transformation and debt restructuring."
Sanjeev Gupta, executive chairman of GFG Alliance, said: "Through the hard work and determination of our team, our Australian integrated operations are now profitable and performing the best they have for many years.
"The deal we have agreed today provides a stable financial platform for our LPMA business and secures a recovery plan for Credit Suisse Asset Management and Greensill Bank following the collapse of Greensill Capital."
Roy Rickhuss, general secretary of the Community union, said: "This news is well overdue, but it's an important step in the right direction and demonstrates that GFG can raise funds for the UK.
"Huge challenges remain but the workforce is ready to get back to making the best steels money can buy, and the £50 million injection will enable us to restart steelmaking. The Government must play their part and act now to protect our industry from the consequences of soaring energy prices."
Local MP and Labour's shadow defence secretary John Healey said: "This is a breakthrough after months while Liberty workers have been left in limbo.
"Liberty is at the heart of steelmaking in Rotherham, and we've been holding our breath for the working capital to restart production."
Rotherham MP Sarah Champion said on Twitter: "Hugely welcomed news. Now the Government needs to play its part and commit to use British steel in its infrastructure projects & addressing the high business rates and energy costs."