Enrico Letta has been given a mandate by Italian president Giorgio Napolitano to form a government after months of political paralysis.

Letta's candidacy was supported by the centre-left Democratic Party (PD) - of which he was once considered a child prodigy - and Silvio Berlusconi's People of Freedom Party to which the 46-year-old future PM is linked by family ties.

Described by Italian media as "a man of dialogue and mediation," Letta is the nephew of one of Belusconi's closest aides, Gianni Letta, 78, who served three times as government undersecretary to the media tycoon.

Born in Tuscan city of Pisa in 1966, Letta started his political career in the ranks of the centrist Christian Democracy (DC), in which he chaired the Youth European Group from 1991-95.

After the DC imploded amid the Tangentopoli corruption scandal, Letta turned left. His uncle (then a journalist) joined newcomer Berlusconi.

A graduate in international law at Pisa University with a PhD in European law, Letta's political career with the centre-left got off to a rocketing start.

At the age of 32, he became the youngest government minister in Italy's history when he was appointed by then premier Massimo D'Alema as minister for European policy in 1998.

Two years later he was confirmed in the cabinet after a ministerial reshuffle which saw him put in charge of the industry and commerce ministry.

First elected MP in 2001 and MEP in 2004, Letta's career crossed that of his uncle Gianni in 2006.

As Romano Prodi won the elections against Berlusconi, Letta succeeded his uncle as government undersecretary.

When the Prodi administration fell a year later, Letta lost the subsequent PD leadership elections to Walter Veltroni, picking up just 11 percent of ballots and finishing third.

In 2009 PD secretary Pier Luigi Bersani appointed him as his deputy and Letta remained the party's No 2 until Bersani quit this week.

Married to Corriere della Sera journalist Gianna Fregonara, with whom he has three children, Letta is known for his low profile and mild manner.

Summoned to the Quirinale presidential palace to be offered the mandate to form a government, Letta arrived driving his own economy Fiat.

"I've accepted [the mandate] with great humility and awareness of my own limits," Letta said. "I'm determined to carry out the mission the president has decided to task me with."

Like his uncle, Letta is a football fanatic and supports AC Milan, the club owned by Berlusconi.

Enrico and Gianni Letta
Enrico Letta with his uncle Gianni (Twitter)