Del Torchio, known as a turnaround expert, has been assigned all operational responsibilities, it said in a statement.
He will replace Andrea Ragnetti, who quit after only a year in the job in February after the struggling airline company posted a 2012 net loss of 280 million euros ($365 million) which had deepened from 69 million euros in 2011.
Alitalia, which is 25 percent owned by Air France-KLM, suffered last year from a drop in demand for air travel amid the euro zone debt crisis and recession in Italy.
The airline said a shareholders’ meeting will take place on April 29.
Alitalia was rescued from bankruptcy in 2008, when it was bought by a consortium of Italian companies including Intesa Sanpaolo, road operator Atlantia and IMMSI , which also controls scooter maker Piaggio.
Air France-KLM, which has held its stake in Alitalia since January 2009, has said it will probably wait until at least 2014 before using an option to take control of the airline.
Reporting by Francesca Landini. Editing by Elaine Hardcastle.