With boyish good looks and an easy-going manner, 31-year-old Di Maio symbolizes a strategic shift for the anti-establishment party from the frantic conspiratorial ranting of iconoclast founder and stand-up comedian Beppe Grillo to a new measured, reassuring style.
If the last major polls were correct, under Di Maio's leadership Five Star (M5S) will become Italy's largest party following the March 4th election.
To achieve that the party intends to use its newly "mature" image to capture voters from the traditional parties that 69-year-old Grillo long railed against.
Instead of the expletive-filled rants of his shaggy-haired former boss, Di Maio offers calmer, considered political reflections.
"We do not want a populist, extremist or anti-European Italy," Di Maio said last year, in a marked change from Grillo's instinctive euroscepticism.
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Beppe Grillo (L) and the party's new leader Luigi Di Maio with the Five Star Movement's new logo. Photo: Andreas Solaro/AFP
The revamping is a double-edged challenge though: Di Maio must appeal to moderate voters without alienating the radicalised portion of the electorate who took the movement into parliament in 2013.
"He is very popular among the party faithful and his strength lies precisely in being completely different from Beppe Grillo, both in his communication style and in his appearance," said Alberto Castelvecchi, a professor at Rome's Luiss University.
But despite the apparent differences, Di Maio is very much a Grillo disciple.
He has been involved with M5S since its creation in 2009, campaigning against corruption and the EU while promoting political transparency and direct democracy.
Following the February 2013 election, M5S won a spectacular quarter of the vote and Di Maio, then aged just 26, was among 108 M5S candidates elected to the Chamber of Deputies -- the lower house of the Italian parliament.
A month later he became the chamber's youngest ever vice-president.
His astonishing ascent did not go unnoticed and the nature of his elevation to rank of prime ministerial candidate also raised eyebrows.
Selected via an online vote, in which Di Maio's competitors were relative unknowns, many commentators branded his election as a coronation organized by "puppet-master" Grillo.
"Is it the man who is being chosen or his readiness to take orders and advice?" asked newspaper La Stampa.
Others questioned his political authenticity, accusing him of being a hybrid creation of Grillo and consultants.
"Di Maio was created to be moderate, reassuring to mums," according to Italian political journalist Jacopo Iacoboni.
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Photo: Tiziana Fabi/AFP
Di Maio was born on July 6th, 1986 into a well-to-do family in Avellino.
His father Antonio had a small construction business and was an activist for a now-defunct neo-fascist party Italian Social Movement, while his mother Paola was a Latin teacher.
The eldest of three children, Di Maio studied computer engineering at Naples University, later switched to law and never completed a degree.
According to a CV posted on M5S's website, Di Maio founded his own web and social media marketing business while studying, as well as working on video projects.
That focus on marketing and presentation helps explain why M5S has managed to shift its to tone on key issues with Di Maio at the helm.
The party had consistently called for Italy to leave the EU and the euro, but Di Maio recently made more conciliatory noises about the idea of staying in the bloc.
His reaction was also noted following the murder of a teenage girl, blamed on a Nigerian, and a far-right revenge shooting that left six African migrants injured in Macerata earlier this month.
Amid a public outcry, Di Maio stayed silent on the gun rampage and instead focused on former prime minister Silvio Berlusconi for creating the "ticking social time bomb of immigration".
"On matters like ethics and immigration," wrote Catholic weekly Famiglia Cristiana, Di Maio ideas are "like those of a surfer riding a wave".
Di Maio's balancing act means M5S is on course to become the single biggest party in a parliament that his mentor Grillo once promised to "open up... like a tin of tuna".
But Di Maio is unlikely to become prime minister, particularly as M5S has repeatedly ruled out governing with other parties -- although he recently said he could seek support from rival forces.