He has pledged to dismantle the Central Bank, replace the Argentine peso with the US dollar, slash social subsidies and halve the number of government ministries.
As a symbol of the deep cuts that he planned to implement, he often campaigned with a revving chainsaw in hand.
“I was born in 1977 and this is my fourth economic crisis,” said Alida Aranda, aged 46, as she waited eagerly with her 16-year-old son to watch Mr Milei vote on Sunday afternoon.
“Even our children have learnt that their pocket money becomes worthless, that there is no point in saving. This change will be good for us. Any change would be good.”
On Monday, Mr Milei confirmed that he will cut all public works and that “those in progress” will be put out to tender.
He added that he will pursue aggressive and front-loaded fiscal consolidation measures, and will probably lift most of Argentina’s currency and trade controls.
Chief on his list will also be the move towards dollarisation, though this is likely to be a long and volatile process, and he will likely need to restructure the country’s $44 billion debt with the International Monetary Fund.
He also vowed “a limited government, respect for private property and free trade” adding that the “model of decadence has come to an end”.
‘Likely to lead to social turmoil’
Analysts however warned that Mr Milei’s proposed reforms would lead to short-term economic pain.
“Even a light version of ‘Mileionomics’ would be likely to lead to social turmoil,” Richard Lapper, from Chatham House, told the Telegraph.
“Drastic spending cuts are certain to increase poverty and joblessness.”
He warned that Argentina’s powerful Left would fiercely oppose the changes, with strikes and street blockades probable.
Ahead of voting, more than 100 economists had penned an open letter warning that Mr Milei’s plans would cause economic “devastation” and social chaos.
The scale of Mr Milei’s victory was unexpected, winning 21 of 24 provinces.
But despite the widest victory margin in a presidential race since the South American country’s return to democracy in 1983, the election exposed deep fractures and historical wounds.
The self-proclaimed “anarcho-capitalist” sparked fierce debate for questioning the number of those forcibly disappeared by Argentina’s 1976-83 bloody military dictatorship, denying that humans have a role in causing climate change, and opposing feminist policies.
He also suggested that people should be allowed to sell their own vital organs, and is against abortion, which Argentina legalised in 2020, proposing a plebiscite to repeal the law.
In a final bid to win over the country’s moderates, Mr Milei backpedalled on some of his more controversial statements, such as loosening gun restrictions, and also avoided criticising Pope Francis, an Argentine, having previously labelled him a “filthy Leftist”.
Thatcher was one of ‘the great leaders’
His anger at the Left, which has been blamed for sending the peso into freefall by “printing money”, is strong.
After his election, a recent video was circulated widely of him attacking the “woke” establishment, and stating: “You can’t give s--- Leftards an inch.”
His rival candidate, Sergio Massa, who is the current economy minister, was widely considered the “continuation candidate” of the current government – a deeply unpopular administration that has been blamed for the economic crisis.
Anti-incumbency sentiment was strong among voters at the polling stations.
Conceding defeat on Sunday, Mr Massa said: “Argentinians have chosen another path.”
Mr Milei captured the world’s attention for his aggressive and theatrical style.
During campaigning, he praised his dogs as his “best advisors” and claimed that he was a tantric sex expert.
His girlfriend, Fátima Flórez, an actress, is known for her impressions of Argentina’s vice-president and former leader Cristina Fernández de Kirchner.
He has also been known to don a superhero costume of his “alter-ego” General Ancap (short for “anarcho-capitalist”) to sing about Argentina’s economic crisis.
The “lion”, as he calls himself, also lauded Margaret Thatcher – who is reviled in Argentina for ordering the sinking of the General Belgrano cruiser – as one of “the great leaders in the history of humanity”.
‘Now we have to give him a chance’
However, he has asserted Argentina’s “non-negotiable” sovereignty over the Falklands, which Argentina refers to as the Islas Malvinas.
“We had a war – that we lost – and now we have to make every effort to recover the islands through diplomatic channels,” he said in the final televised election debate.
In recent weeks, Mr Milei has backed Israel and condemned Hamas’s Oct 7 attacks on the country.
In an interview with The Times of Israel, he said that an Argentine rabbi is his spiritual guide and that he would move the country’s embassy to Jerusalem.
Political realities may constrain some of Mr Milei’s more radical ambitions: his party has only 35 of the 257 seats in the lower house and seven of the 72 senate benches, leaving him dependent on more conservative centre-Right parties.
Nevertheless, the mood in the capital on Sunday night was one of jubilance as supporters arrived in their thousands, waving Argentina flags, launching fireworks, honking horns and singing to popular Latin American rock music.
One Massa voter told the Telegraph that, while he feels disappointed by the result, “now we have to give him a chance”.
Lorenzo, aged 31, added: “Maybe I will be mistaken.”
