According to projections around one in four voters in Sunday’s election backed Meloni’s Brothers of Italy party, which has post-fascist roots.
But the party leads a coalition set to win a majority in parliament.
As of Monday morning the count was still in progress, but the centrodestra right-wing alliance led by Brothers of Italy were set to claim over 44 percent of the vote, making it the clear victor.
Coalition partners Matteo Salvini’s far-right League and former premier Silvio Berlusconi’s Forza Italia lagged behind her in the polls, with 9 and 8.3 percent respectively.
Her success represents a seismic change in Italy, a founding member of the European Union and the eurozone’s third largest economy – and for the EU, just weeks after the far-right outperformed in elections in Sweden.
Meloni, who campaigned on a motto of “God, country and family”, is expected to become Italy’s first female prime minister, although the process of forming a new government could take weeks.
At a time of soaring inflation, a looming energy crisis and the war in Ukraine, the 45-year-old sought to reassure those worried about her lack of experience and radical past.
Meloni said voters had sent a “clear message” of support for her party to lead their right-wing coalition to power.
“If we are called to govern this nation we will do it for all Italians. We will do it with the aim of uniting people, of enhancing what unites them rather than what divides them,” she told reporters.
Full results are not due until later Monday but the centre-left Democratic Party, the coalition’s main rivals, conceded, saying it was a “sad” day.
Turnout fell to a historic low of around 64 percent, about nine points lower than the last elections in 2018.
Meloni no longer wants Italy to leave the eurozone but says Rome must assert its interests more, and has policies that look set to challenge Brussels on everything from public spending rules to mass migration.
Congratulations came in quickly from her national populist allies across the continent, from Polish Prime Minister Mateusz Morawiecki to Spain’s far-right party Vox.
“Meloni has shown the way for a proud, free Europe of sovereign nations,” Vox leader Santiago Abascal tweeted.
Meloni had been leading opinion polls since Prime Minister Mario Draghi called snap elections in July following the collapse of his national unity government.
Hers was the only party not to join Draghi’s coalition when, in February 2021, the former European Central Bank chief was parachuted in to lead a country still reeling from the coronavirus pandemic.
From a “very aggressive” opposition strategy under Draghi, Meloni then chose a “very cautious, very reassuring campaign”, Lorenzo De Sio, head of Italian electoral studies centre CISE, told AFP.
“Her challenge will be to turn this electoral success into a governing leadership… that can last,” he said.
Italian politics is notoriously unstable, with nearly 70 governments since 1946, and Meloni, Salvini and Berlusconi do not always agree.
Meloni’s “dissatisfied and essentially defeated allies” would likely be a “problem”, the Corriere della Sera newspaper said.
The League and Forza Italia looked to have performed poorly, taking eight percent each, down from 17 and 14 percent respectively in 2018.
As provisional results emerged, Salvini hailed the coalition’s victory, tweeting “Grazie! (Thanks!)” while Berlusconi called Meloni to congratulate her.
Brothers of Italy has roots in the post-fascist movement founded by supporters of Benito Mussolini, and Meloni herself praised the dictator when she was young.
She has sought to distance herself from the past as she built up her party into a political force, going from just four percent of the vote in 2018 to Sunday’s projected triumph.
Her coalition campaigned on a platform of low taxes, an end to mass immigration and Catholic family values, which critics fear will see a reversal in hard-won rights such as abortion.
A straight-speaking Roman raised by a single mother, Meloni rails against what she calls “LGBT lobbies”, “woke ideology” and “the violence of Islam”.
The coalition also wants to renegotiate the EU’s post-pandemic recovery fund, arguing that the almost 200 billion euros ($193 billion) Italy is set to receive should take into account the energy crisis.
But the funds are tied to a series of reforms only just begun by Draghi, and analysts say she has limited room for manouevre.
Despite her euroscepticism, Meloni strongly supports the EU’s sanctions against Russia over Ukraine.
However Berlusconi, the billionaire former premier who has long been friends with Vladimir Putin, faced an outcry last week after suggesting the Russian president was “pushed” into war by his entourage.