The announcement follows a rescue deal between Alitalia and the Abu Dhabi-based Etihad Airways, which will take a 49 percent stake in the debt-laden carrier.
"I am proud to welcome our new board as we embark on this exciting phase in our airline's history," said Montezemolo, who has been appointed for three years.
"The diversity and depth of their cumulative experience and knowledge will be pivotal in supporting and guiding the implementation of the business plan and the successful turnaround of Alitalia," he added.
Etihad chief James Hogan was appointed vice chairman.
The board has nine directors, six appointed by Alitalia and three by Etihad, including the vice chairman.
Etihad is expected to invest €560 million in the Italian airline, which has lurched from crisis to crisis for years.
Key stumbling blocks in the drawn-out merger negotiations had been Alitalia's debt of about €1.0 billion and overstaffing issues.
Montezemolo was ousted from his role as president of flashy sports brand Ferrari in September after 23 years amid a strategy clash with the board.