Greece’s outgoing prime minister, Alexis Tsipras, has handed over power to Kyriakos Mitsotakis, a former banker who navigated the centre-right New Democracy party to landslide victory in Sunday’s snap general elections.

In a changing of the guard that was as subdued as it was swift, Mitsotakis assumed office after he was officially sworn in by the Orthodox Christian country’s spiritual leader, Archbishop Ieronymos.

Hours later, a new government was announced: of its 51 members, 21 were untested politicians, some from centre-left backgrounds, some technocrats, some from the world of business who had come on board “to help the country turn a new page”.

Profile Who is Kyriakos Mitsotakis? Show Hide In style and background Greece’s new leader Kyriakos Mitsotakis could not be more different to his predecessor Alexis Tsipras. Born in 1968 into one of the country’s powerful political dynasties, his father Konstantinos Mitsotakis also held the office of prime minister. As Mitsotakis’ only son, Kyriakos seemed destined to go into politics too. After being educated at Greece’s elite Athens College, he was sent to Harvard University where he graduated with a degree in social studies in 1990. But after continuing his studies – earning an MA in international relations at Standford University and an MBA from Harvard's Business School - he took a different path. He went to London to work as a financial analyst with Chase Investment Bank, and then as a consultant with the business company McKinsey. It wasn’t until 2004, seven years after returning to Greece to continue his financial career, that he ventured into politics and ran for parliament. Like his father, Mitsotakis saw himself as a liberal centrist who cared about green issues and human rights. From 2013 to 2015 he served as minister for administrative reform in the coalition government headed by Antonis Samaras. During his tenure thousands of civil servants were laid off, igniting fierce criticism from political opponents. In January 2016, when the New Democracy party had been riven by Greece’s economic crisis, he decided to run for the leadership, but had little support and soon discovered his name was more of a hindrance than a help. He eventually won the post, but only after running what aides describe as a tough campaign. Once he assumed the leadership, his overhaul of New Democracy began, culminating with the party returning to power in 2019. Photograph: Louisa Gouliamaki/AFP

From the outset, there was no escaping the change in style. In a radical departure from his leftwing predecessor, a self-declared atheist only ever seen in open-neck shirts, Mitsotakis wore a suit and tie as he took the oath on the Bible, watched by his wife and three children.

Facebook Twitter Pinterest Mitsotakis at the swearing-in ceremony. Photograph: Pantelis Saitas/EPA

“We have been given a strong mandate to change Greece,” said the 51-year-old in his first statement as prime minister after his investiture. “The hard work begins today. I have absolute confidence in our abilities to rise to the occasion.”

The change not only marked a return to power for the conservatives, but also the start of a new era: after a drama-filled decade of deep recession, multiple international bailouts and unprecedented poverty and protest, debt-stricken Greece had come full circle, electing its first post-bailout government.

In a nation worn out by years of EU-mandated austerity – the price of remaining in the eurozone – Mitsotakis’s promise of re-energising the economy has resonated.

His pledge to reduce taxes and create jobs in a county still grappling with record unemployment – at 18%, the highest in the EU – particularly appealed to the middle class hit hard by tax rates imposed by the Tsipras government to meet fiscal targets.

“Psychologically, it feels like there has been a change. The economy has been at a standstill and foreign investors like this guy,” said Stelios Kapezos, the owner of a cafe frequented by politicians close to the parliament. “But he’s not going to have long to prove himself. He said he would bring down VAT and other taxes, and we want to see that. Tsipras said so many things and never delivered. We need to start seeing some positive change soon.”

With all votes counted on Monday, New Democracy was shown to have captured 39.8% and 158 seats, more than doubling its presence in the 300-seat parliament. Tsipras’s Syriza party won 31.5%.

Furnished with an absolute majority, Mitsotakis, the son of a former conservative prime minister, was able to form a government unfettered.

Insiders say the new Harvard-educated leader’s overarching aim will be to unify an often fractious nation behind a reform plan that will spur economic growth. “I don’t think there has been a prime minister who has been more prepared for this job,” said one. “He knows what he is up against, he has a plan, and he is going to act on it.”

Facebook Twitter Pinterest Alexis Tsipras hands over to his successor, Mitsotakis. Photograph: Angelos Tzortzinis/AFP/Getty Images

The new cabinet will be sworn in on Tuesday. Mitsotakis may have a fiery start: tensions with Turkey have risen dangerously in the eastern Mediterranean over conflicting claims to energy reserves off the island of Cyprus. In a move that has alarmed the EU, Ankara announced that it would be sending a second drilling ship to begin the search for hydrocarbons off the island on Tuesday.

Congratulatory messages poured in for a politician viewed internationally as a reformist whom supporters say is the man to modernise Greece. Despite Tsipras’s promises of relief measures, including a bonus for pensioners and wage increases, Mitsotakis resolutely refused to make pre-election promises he said he would be unable to keep – even if his party’s pledge to reduce VAT and corporate and property taxes is likely to engender disapproval among foreign creditors who have continued to monitor Greece since it exited its third economic adjustment programme last August.

In a previous guise, the politician was minister of administrative reform, making changes to the public sector that, while controversial, were widely respected by foreign lenders.

Although New Democracy has traditionally espoused socially conservative views, as one of Europe’s most nationalist rightwing parties, Mitsotakis has been at pains to move it to the centre. Privately, he describes himself as a progressive with liberal economic views.

The party’s victory has been seen as a personal vindication: as a modernising centrist, the ex-financier had been held in suspicion by leading figures in New Democracy when he took the helm in January 2016.