Firecrackers exploded and supporters danced in the street, tears in their eyes, after it emerged that Narendra Modi had led the Bharatiya Janata Party to a historic landslide win in India’s general elections, paving the way for him to become the country’s 14th prime minister.

Trumpeted as a “tectonic shift” for politics in the world’s largest democracy, the scale of the BJP’s win surpassed the expectations of India watchers and even the party itself, after record-high voter turnout.

The BJP rocketed from 116 to 282 seats in the 543-member lower house of Parliament, which follows the first-past-the-post Westminster system. Easily topping the 272 seats needed to govern in India, BJP is the first party to win a single party majority in 30 years.

It was the worst result in history for the ruling Indian National Congress party, which dropped from 206 to just 44 seats. Having dominated Indian politics since independence in 1947, led mostly by the Nehru-Gandhi dynasty, Congress is now suffering the embarrassment of needing to join an alliance to properly sit in opposition. While Congress President Sonia Gandhi and her son Rahul — who was being prepped to lead the country — held their seats, there was a nail-biting moment where it looked like the 43-year-old Gandhi scion would lose.

But now, as Modi does the rounds of victory speeches, preparing to take his oath as prime minister in New Delhi’s Parliament on May 21 and settle into five years in office, a sense of awkwardness hangs over the city’s foreign correspondent club.

Modi was always a polarising candidate. While the source of his controversy was picked over by Indian media, none were pickier than the foreign press. The Economist magazine went so far as to run a cover amid the height of campaigning urging readers to vote against him. “Can anyone stop Narendra Modi? He will probably become India’s next prime minister. That does not mean he should be,” the magazine declared.

So who is Modi and why are some people so scared of him? With a trim grey beard, penchant for Bulgari spectacles and traditional linen shirts tailored by a clothing chain going gangbusters with its recently trademarked “Modi Kurta”, 63-year-old Narendra Modi will be the first Indian PM born in the post-independence era.

He grew up in a lower-middle class home in the western state of Gujarat, where his father worked as a railway tea vendor. When he was eight years old Modi joined the Rashtriya Swayamsevak Sangh, a Hindu nationalist volunteer organisation formed during India’s independence movement that strives for “assimilating Indian society to a particular set of Hindu norms, and achieving Param Vaibhav, or ultimate glory, for Bharat [as the organisation prefers to call India] by making it the vishwa guru, or guide to the world”.

After an arranged marriage that was never consummated, Modi rose through the ranks of the RSS and in 1985 was thrust into the BJP — which shares ideology and workers with the RSS. In 1990 he joined a march to a contested holy site in Ayodhya — an issue that sparked Hindu-Muslim clashes and the deaths of 2000 people two years later.

In 2001 Modi was chosen to replace Gujarat’s chief minister. He has remained in the top job ever since, becoming the state’s longest-serving chief and winning praise for cutting red tape and creating a business environment that helped the state economy nearly triple in size.

The black mark that shadowed Modi throughout the campaign came in 2002 when mass riots broke out in Gujarat, resulting in the deaths of more than 1000 people — mostly Muslims. Human Rights Watch reported that Modi’s administration was complicit and the attacks planned, “with the extensive participation of the police and state government officials”. Victims told of police refusing to help, saying they had no orders to stop the bloodbath. In the fallout Modi was banned from entering the United States and Britain. Former BJP minister Maya Kodani was booked for orchestrating the massacre of 95 people and jailed for life. Modi has been investigated but never convicted.

“I firmly believe that the emergence of India as a major powerhouse of the evolving global economy is an idea whose time has come.”

Modi went into the electoral battle against a 128-year-old ruling party, born in the independence movement and past its glory days. During Congress’ last 10 years at the helm India’s once-shining economy turned dull. GDP growth topped 9% for some of the past decade but dimmed to less than 5% in the last two years; for the past three years, inflation was the highest in 20 years. Alongside this, a string of corruption scandals fuelled massive protests while Rahul never shook the image of himself as a reluctant politician dragged into the family business.

Meanwhile, putting his controversial past behind him, Modi campaigned on a fierce pro-development platform, cutting across India’s traditional divisions of caste and ethnicity. A smart move in a country where unnerving economic disparity results in trash pickers surviving on a few dollars a day, cleaning up after industrialists with $100,000 cars and private jets. While Modi didn’t divorce himself from his Hindu nationalist roots — staging a rally near Ayodhya against the backdrop of a massive picture of the Hindu god Lord Ram — he mostly talked about ending corruption and fixing the economy, the world’s third largest in terms of purchasing power parity according to World Bank figures. Modi said in a rare interview with The Times of India:

“Today it is anachronistic to think that a community won’t be interested in development and good governance. In fact, it is an insult to the intellect of the Indian voter by such parties that believe that he can be made to forget about real issues of poverty and development and get him to vote in a particular manner just by making him insecure by fear-mongering.”

Indian Express editor Shekhar Gupta concluded:

“This is a victory achieved primarily on an unqualified promise of economic reform never seen in our political history, soaked as it is in the fading pink of fake socialism. This result, therefore, is also a devastating popular rejection of outdated, Congress-style povertarianism: I declare all of you Indians hungry and wretched and will throw free food at you.”

“Modi promised the moon and stars to the people. People bought that dream,” senior Congress leader Rajeev Shukla told reporters.

Modi led a mammoth campaign, reaching out to the country’s 814 million voters with 196 rallies across 25 states in the five-week election period. He dominated the digital attack on Facebook and Twitter, sent recorded messages on mass to mobile phones and appeared onstage via hologram, declaring: “Only Modi can save India.”

The result was a clean sweep for the BJP in the states of Gujarat, Delhi, Rajasthan, Himachal Pradesh and Uttarakhand. The BJP’s National Democratic Alliance bagged a total 336 seats, beating the previous best result against Congress of 302 won by the Janata Party in 1977 on the back of Indira Gandhi’s Emergency years.

India’s Sensex hit record highs above 25,000 as votes were counted and Modi’s thumping success became clear, highlighting the backing his economic dream has from the corporate world. The Congress held onto 44 seats, less than half of its worst-ever result of 114 in 1999. With the United Progressive Alliance, it now has 59 seats.

India’s new Aam Aadmi Party — formed off the back of anti-corruption protests and seen as a dark horse after it unexpectedly came to power in Delhi’s state election — took home four seats. The party’s leader Arvind Kejriwal, an activist and former tax official, lost to Modi in the battle for the seat of Varanasi.India’s new Prime Minister is expected to make sweeping reforms to reignite growth, investing in infrastructure and manufacturing and working fast to make jobs for India’s 1.2 billion people, half who are under the age of 25. “The next war that is going to be fought globally is the ‘jobs war’,” he told The Times of India.

On the world stage, commentators expect Modi to stay true to his tough guy “with a 56-inch chest” image, although most of his statements on foreign relations have been mainstream, including not wanting to take a “confrontational” approach with India’s neighbours. Abhijit Majumder wrote in The Hindustan Times:

“[Past leaders] wanted India to be the compassionate statesman, visionary, charming talker, global peacenik. Modi is likely to make it competitive, determined, hard and mean if need be – a nation which makes sure it takes at least a little bite more than it gives.”

People will keenly watch how Modi handles India’s historically tense Hindu-Muslim relations. Dr Manmohan Vaidya, spokesman for the RSS  — which has roughly 40 million members across India and surged in popularity on the “Modiwave” — says he hopes the new prime minister will fulfil his campaign promises, including building a temple at the controversial Ayodhya site. “It’s important for everybody, their emotions are attached to that, their pride is attached to that,” he said.

The incoming prime minister is “definitely not going to be launching any policy discrimination against Muslims but definitely has increased anxiety among the Muslims,” according to journalist Nilanjan Mukhopadhyay. Having met Modi while writing his biography, Mukhopadhyay said he did not expect him to offer any symbolic gestures to appease Muslims, who make up around 15% of the population. “I think it’s a great tragedy for a party with 282 seats to not have a single Muslim. In a country as diverse as ours, this is not great,” he said.

Now 1.2 billion pairs of eyes belonging to India’s increasingly aspirational and impatient citizens, around a sixth of the world’s population, are trained on the former tea seller expecting big, big things. “The world will rediscover India if Narendra Modi can address the problems of slow growth and high inflation,” the head of emerging markets at Morgan Stanley, Ruchir Sharma, declared.

But the final word is perhaps best left with outgoing Congress Prime Minister Manmohan Singh, the noted economist credited with first igniting India’s economic engine with reforms in the 1990s. Wishing Modi luck, he said:

“I firmly believe that the emergence of India as a major powerhouse of the evolving global economy is an idea whose time has come.”