Movement members cast ballots online for one of eight candidates but there was never any contest as Di Maio, the 31-year-old vice president of parliament's lower chamber, was the only well-known choice. In accepting the post, Di Maio essentially kicked off his campaign for the premiership.
"In the coming months, Italy must choose whether it wants to continue to survive or start to live," Di Maio said. "If it wants to live, it should choose a 5-Star government." Party members hope that Di Maio, a native of Naples, can effectively articulate the party's anti-establishment, anti-banking, pro-environment message. He was first elected to parliament in 2013 and, at 26, became the youngest-ever vice president of the lower Chamber of Deputies.
The 70-year-old Grillo, a comic who turned his upstart populist movement into the biggest opposition party in parliament, has been intent on turning the movement over to a new generation. But he showed no signs of disappearing Saturday: As soon as Di Maio was crowned, Grillo took the stage for one of his trademark monologues.
"I'm the founding father, but I'm here," Grillo said. Italy's next general election must be held by spring. Recent polls put the 5-Stars head-to-head with the ruling Democratic Party of ex-Premier Matteo Renzi as the largest single party vote-getter, with around 26 percent of the vote.
But the 5-Stars have ruled out forming a coalition. Recent surveys have given a hypothetical center-right coalition of Silvio Berlusconi's Forza Italia party, the anti-immigrant Northern League and smaller parties around 34 percent of the vote.
Lawmakers are currently haggling over a new electoral law that will determine what a future government could look like. At a campaign-style event this week, the 80-year-old Berlusconi dismissed Di Maio as a "political meteorite who looks good on TV but brings nothing to Italians."
Grillo, for his part, poked fun at Berlusconi's umpteenth political return, saying he hopes he doesn't end up on the campaign trail at Berlusconi's age. Neither Berlusconi nor Grillo can actually run for office. Grillo is barred by a 1981 manslaughter conviction stemming from a car accident, whereas Berlusconi is currently barred due to a tax fraud conviction.