Prodi formed Italy's 61st postwar government on Wednesday, after his center-left coalition scored a razor-thin victory in April 9-10 parliamentary elections and ousted Silvio Berlusconi's conservatives from power.
The victory, however thin, put the 66-year-old Prodi in a unique position: He is the only man ever to defeat Berlusconi in an election- and has done so twice.
Nicknamed "Il Professore," Prodi is known for his passions for cycling and jogging, and is often drawn in cartoons as a priest clad in black. Aides and friends say that beneath this soft image lies a resolute leader; critics say he is a Euro-phile technocrat with little soul and a condescending attitude.
His style could not be more different from Berlusconi's over-the-top, flamboyant personality: Prodi has a soft monotone voice, and is often accused of being boring and lacking charisma.
Yet a strong leadership is exactly what he may need, after an election that he had been expected to win more easily, the AP reports.
His bloc is made up of forces as diverse as Communists and Christian Democrats. The two main parties, the centrist Daisy and the Democrats of the Left, have been locked in a struggle of power over how many and what posts they each should get in the Cabinet.
As premier from 1996 to 1998, Prodi won plaudits for putting Italy's shaky finances in shape in time to adopt Europe's single currency, the euro. Now, his toughest challenges will be reviving the economy, which is mired in stagnation, while trying to cut its debt and deficit to levels in line with the rules for European monetary union.