Center-left leader Enrico Letta forged a new Italian government Saturday in a coalition with former Premier Silvio Berlusconi's conservatives, an unusual alliance of bitter rivals that broke a two-month political stalemate from inconclusive elections in the recession-mired country.
The daunting achievement was pulled off by Letta, who will be sworn in as premier along with the new Cabinet at the presidential Quirinal Palace on Sunday.
Letta, 46, is a moderate with a reputation as a political bridge-builder. He is also the nephew Berlusconi's longtime adviser, Gianni Letta, a relationship seen as smoothing over often nasty interaction between the two main coalition partners.
Serving as deputy premier and interior minister will be Berlusconi's top political aide, Angelino Alfano. He is a former justice minister who was the architect of legislation that critics say was tailor-made to help media mogul Berlusconi in his many judicial woes.
The creation of the coalition capped the latest political comeback for Berlusconi, a former three-time premier who was forced to resign in 2011 as Italy slid deeper in to the eurozone's sovereign debt crisis.
On Monday, Letta is expected to lay out his strategy to Parliament, before required confidence votes from the Chamber of Deputies and the Senate.
(Read More: Why Italy Is a Safer Bet Than Spain: Strategist)
"We negotiated for the formation of the government without throwing up any stop signs," Berlusconi told one of his TV networks. "That's how we contributed to forming a government in short time" after Letta was tapped Wednesday.
Berlusconi, a fervent anti-Communist, views Italy's left as a personal nemesis, and Letta's Democratic Party has some of its roots in what was the West's largest Communist Party.
Letta expressed "sober satisfaction over the team we put together and its willingness" to form a coalition.
Although Letta strove to fill his Cabinet with new faces, a longtime Italian central bank official, Fabrizio Saccomanni, who also served a stint at the International Monetary Fund, was chosen for the key economy ministry portfolio.
In the role, Saccomanni will have to balance European Union insistence on rigorous austerity to heal Italy's finances with politicians' sensitivities to voters. The public's patience has been tried by spending cuts and higher taxes without seeing the start of any economic revival.
Only a few weeks earlier, the head of the Democrats, Pier Luigi Bersani, resigned from the party post in humiliation and he refused Berlusconi's offer for a "grand coalition" and futilely tried to form a government without the center-right. Letta was a Bersani loyalist.
Bersani hailed the coalition formula as a "necessary compromise" that gives the country "freshness and solidarity."
The No. 3 bloc in Parliament, the anti-establishment 5 Star Movement, is led by comic Beppe Grillo, who ruled out any alliance with the largely sullied political class that has ruled Italy for decades.
President Giorgio Napolitano, who tasked Letta with creating a government out of bitter rivals, called upon the coalition partners to work "in a spirit of absolute, indispensable cohesion" as they work for sorely needed political and economic reforms.
The 87-year-old head of state sounded almost breathless as he expressed confidence the rivals could work together "without conflict or prejudices to find the right solutions" to the country's pressing economic and political problems.
Napolitano didn't name the challenges, but they include fighting unemployment, especially for young people, and corruption sullying much of the political class.
Napolitano said: "It was and is the only possible government," and one "whose formation couldn't be delayed further, in the interest of our country and of Europe."
He reluctantly agreed to be re-elected by Parliament earlier this month for another seven-year term because of the political instability.
Italy's economy is No. 3 among eurozone members, and financial markets have been anxiously watching to see if an effective government could be formed to carry on with outgoing Premier Mario Monti's efforts to keep the country from sliding into the eurozone's sovereign debt crisis.
(Read More: Italy's New Leader Throws Down Gauntlet on Austerity)
Some Italian political observers have predicted such a hybrid government might last only a few months of Parliament's five-year term, before collapsing in squabbling.
But the fear of elections, especially after the lightning-quick rise of comic Grillo's grassroots movement, could prove to be strong glue.
Giovanni Orsina, deputy director of LUISS university's school of government in Rome, ventured that Letta's new coalition could "last more than we expect, 18 to 24 months, more or less."
The history professor cited "lack of alternatives, and because I believe Parliament's members are not particularly eager to get back to the polling booth and face new elections."
Voters, fed up with new and higher taxes, including a despised property tax revived by Monti, rejected his severe austerity policies.
The small centrist party created in time for the election by Monti, an economist and former European Union commissioner, will participate in the coalition, although Monti won't be in the Cabinet, which is heavy on two novelties -- a large presence of female ministers and Italy's first black minister.
A native of Congo, Cecile Kyenge is a doctor who will serve as minister of integration. Proposals to make it easier for Italy' growing immigrant population to become citizens have gone nowhere in Parliament amid fierce opposition from the anti-immigrant Northern League party. The party, a Berlusconi ally, isn't in the new government.
Prominent among the women in the Cabinet is Emma Bonino, a former EU commissioner and Radical Party leader who will serve as foreign minister. Olympic gold medal kayaker Josefa Idem was tapped as minister of equal opportunity and sports.
(Read More: CNBC Explains 'PIIGS')
Letta comes from a moderate wing of the left-rooted Democratic Party that is close to the Vatican. Since Parliament always includes an array of lawmakers enjoying good ties to the politically influential Catholic church in Italy, this was one more qualification on Letta's bridge-building resume.
The father of three sons, he lives in Rome's working-class Testaccio neighborhood. When he was tapped by Napolitano on Wednesday, he drove his own car to the Quirinal Palace, in what was seen as a photo opportunity gesture to Italian taxpayers who widely despise the huge fleet of luxury cars that shuttles around ministers and lawmakers.
In 1998, when he was 32, Letta became the youngest minister in Italy's history when he served as minister for European policy for then-Premier Massimo D'Alema, an ex-Communist leader. Letta seemed a natural for that post. He spent his childhood in Strasbourg, home to the European Parliament, and studied international law before jumping into politics.