Spalletti led Napoli last season to their first Serie A title in 33 years, crowning a long club management career that has included spells at AS Roma, Inter, and a five-year stint with Russian club Zenit St Petersburg.
He stepped aside from the Napoli job in May after requesting a sabbatical and was replaced by Frenchman Rudi Garcia.
The Italian Football Federation said on its website that Spalletti would take up the post from September 1st.
"The national team needed a great coach and I'm very happy that he accepted," federation president Gabriele Gravina said.
"His enthusiasm and his expertise will be fundamental for the challenges that await Italy in the coming months."
A source told Reuters that Spalletti's contract will run until the 2026 FIFA World Cup. The official statement did not specify the length of his contract.
Spalletti will be the national side's ninth coach this century.
His debut match in charge will be Italy's 2024 European Championship qualifier in North Macedonia on September 9th, and the Azzurri will then host Ukraine three days later.
Italy are currently third in Group C on three points from two matches, trailing Ukraine on six points from three games. England lead the group with 12 points after four matches.
