De Blasio's Italian roots have given him a status in Italy usually only reserved for country leaders.
Not only will he be treated to guided tours and lavish lunches over the next week, the American will also become an honorary citizen of his grandmother's hometown in Basilicata.
As the Italian media whipped up the excitement, one newspaper even revealed details of the mayor's lunch on Monday, which will include pasta, risotto and baked sea bass.
In return for the hospitable welcome, de Blasio has pledged to help preserve Rome's heritage, saying he knew of a number of Italian-Americans willing to finance cultural projects and that he is willing to find other potential philanthropists.
“I am available to look for financiers for projects regarding the artistic and archaeological heritage of the capital,” he was quoted in La Repubblica as saying.
Rome is struggling to maintain its numerous ancient sites and monuments, with Mayor Ignazio Marino recently pleading for help from private investors.
The fashion world has stepped in, with Fendi funding the €2.18 million repair work of the Trevi Fountain and the the owner of Tod’s shoes fitting the bill at the Colosseum.
Marino’s efforts appear to have impressed De Blasio, who said Rome “is in good hands”.
“It’s a pleasure to be in Rome, one of the most beautiful cities in the world. There has always been a strong bond between Rome and New York...I hope this to be a fruitful collaboration,” de Blasio said.
The two city mayors toured the Italian capital together over the weekend, described as an “affectionate outing” by Rome daily Il Messaggero.
Marino worked as a surgeon in the US for a number of years, while much has been made of de Blasio’s Italian heritage.
Later this week, he will also visit Sant'Agata de' Goti, his grandfather’s hometown close to Naples, where an additional 300 police officers and private bodyguards have been lined up, Il Mattino said.
He will then travel to Grassano, his grandmother's town in Basicilata, to receive an honorary citizenship.
Amid all the celebration in Italy, the American politician’s visit has gone down less well at home, where the nine-day foreign trip had been criticized for its length.
“At nearly 10 days, [it is] the longest foreign trip by a New York mayor in a generation,” the New York Times noted, describing the visit as “a calculated risk” for de Blasio.