"The Riva Acciaio plants will re-open ," Flavio Zanonato said.
The company had halted operations at seven plants in northern Italy and sent home 1,400 workers after assets and current accounts with €916 million ($1.2 billion) were frozen as part of an investigation into alleged environmental crimes at its sister company, steel giant Ilva.
The Riva family that owns both companies is under multiple investigations for fraud and toxic pollution at its main plant in Taranto in southern Italy.
The company claimed it did not have the resources to keep the plants open.
The closures had sparked protests and Prime Minister Enrico Letta had promised to "put all pressure" on the company to persuade it to reverse its decision, insisting it had enough funds to continue production.
The steel sector as a whole in Italy -- which is dominated by Ilva and the Riva family -- employs around 50,000 people.