Mancini left Zenit on Monday by mutual consent.
The names of former Bayern Munich coach Carlo Ancelotti and Chelsea boss Antonio Conte had also been touted, with Ancelotti reported to have said "no".
"I want to thank the commissioner, and the sub-commissioner Michele". "I would like to be the coach who brings Italy back to the top".
Italy's soccer national team new coach Roberto Mancini smiles during his first press conference at Coverciano Sporting Center, in Florence, Italy, Tuesday May 15, 2018.
FILE - In this Wednesday Dec. 21, 2011 file photo Manchester City's manager Roberto Mancini, right, issues instructions to Italian stiker Mario Balotelli during the team's 3-0 win over Stoke in their English Premier League soccer match at The Etihad Stadium, Manchester, England. His contract will run until 2020, but stipulates an automatic extension should Italy qualify for the European Championships that year, and also includes various incentive-based bonus payments. He takes over from Luigi Di Biagio, the U21 coach, who took charge on an interim basis after Italy crashed out of qualification to Sweden.
Mancini is under no illusions that the rebuild task will be a tough one, but while others are making plans for this summer's World Cup, what can we expect from the new Italy boss?
Roberto Mancini for the first time in his career he headed the national team.