In 2010, when Vichai Srivaddhanaprabha, who has died aged 60 in a helicopter crash, took over the ownership of Leicester City, the idea that he could guide the club to a Premier League title would have seemed fanciful, if not laughable. Even in a previous era, when money talked less loudly, Leicester had never been able to win the old First Division championship. The concept of an essentially small-time club overturning new-era brands such as Chelsea, Arsenal and the two Manchester clubs appeared absurd. No one even spoke about the possibility.

Under Vichai’s reign, however, Leicester not only won the Premier League in 2015-16 but took it in style, winning by 10 clear points and with two games in hand. It was by far the club’s greatest achievement since its foundation in 1884 and, considering the team were 5,000-1 outsiders at the beginning of the season, one of Britain’s biggest sporting shocks.

While the players and their manager Claudio Ranieri (not to mention his predecessor, Nigel Pearson, who had built the side) quite naturally took the acclaim, Vichai’s role in the triumph was never lost on the Leicester fans, who appreciated his over-arching role in the club’s dramatic rise.

Vichai, who paid £39m for Leicester, had taken over when they were in the Championship, having only just emerged from the third tier of English football. He soon began to pour millions into the club, and after a brief dalliance with the former England coach Sven-Göran Eriksson as manager, eventually settled on Pearson to lead the side. Within four years of Vichai’s takeover Leicester had won promotion to the Premier League, and after a difficult first season back in the top flight he showed a decisive and ruthless streak by sacking Pearson. Over the following 10 months Ranieri led them to the promised land.

Many of the details of how Vichai reached that pinnacle are unclear. He was a native of Thailand, thought to have been born in the capital, Bangkok. His birth name was Vichai Raksriaksorn – and Srivaddhanaprabha, which means “light of progressive glory”, was given to him by King Bhumibol of Thailand in 2012. Vichai talked very little of his early years but did mention that as a young man he left to study first in Taiwan and then the US.

It was while travelling that he became interested in the possibility of making money from the duty free business, and in 1989 he was granted a licence to run a small duty free store in Bangkok. By 1995 he had managed to acquire a concession in the city’s old Don Mueang airport, naming his business King Power in honour of the Thai monarch. A key moment came in 2006 when the new Suvarnabhumi airport opened in Bangkok as the country’s main hub for international flights, and Vichai was awarded an exclusive duty-free contract.

The rise from that point was dramatic: taking advantage of this monopoly, Vichai saw his fortune rise to an estimated $200m within a year, and inside another decade it had hit $2bn. Later he diversified, buying substantial stakes in Accor’s Pullman hotels in Thailand and the budget airline Thai AirAsia. By the time of his death he was, according to Forbes, worth about $3.3bn.

The connection with Leicester City arose in 2007, when King Power became the club’s shirt sponsors. Three years later, Vichai bought Leicester from the previous owner, Milan Mandarić, immediately loaning the club £100m to help with the Championship promotion bid and then converting the loan into equity. He also promised to invest a further £180m, although in the end he only had to put up £80m or so, mainly in the form of sponsorship, to deliver the Premier League title.

He made himself chair in 2011, with his son, Aiyawatt, as his vice-chair, and two years later bought the club’s ground, which he renamed the King Power stadium, from a US pension fund manager.

A hands-on owner who respected the club’s heritage and liked to attend as many games as he could, he was an animated supporter on matchdays. Aiming to nurture a family atmosphere at the club, he subsidised coach travel to away games and handed out free beer and food to fans on special occasions. Holding strongly to his Buddhist faith, he installed a shrine in the ground and flew in monks from Thailand to offer up prayers. He also supported charitable causes in Leicester and in his homeland.

However, while Vichai’s years at Leicester were generally looked upon with fondness, they were not without controversy. His dismissals of Pearson and then, only nine months after the title win, Ranieri, were heavily criticised in some quarters, and earlier this year Leicester agreed to pay the Football League £3.1m to settle the league’s long-running claim that the club breached financial fair play rules when it made a £21m loss in the 2013-14 season.

In his business affairs it was noted that Vichai had once been on close terms with the controversial Thai prime minister, telecoms businessman and former Manchester City owner Thaksin Shinawatra, who was ousted in a coup in Thailand in 2006. There were also allegations that King Power had not been paying the Thai government everything it was due from the company’s duty-free franchise at Suvarnabhumi airport, although a court case on the matter was recently dismissed.

Aside from Leicester, Vichai owned the VR polo club in Bangkok (he was a keen polo player) and dozens of racehorses in Britain. In 2017 he bought his second football club, OH Leuven in Belgium.

Before his death he had declared that his main ambition for Leicester, whose value has risen to around £371m, was to make the club “a sustainable and consistently competitive force in the Premier League”, adding: “I’m excited to see the progress we can make.”

He is survived by his wife, Aimon, and their four children, Voramas, Apichet, Arunroong and Aiyawatt.

• Vichai Srivaddhanaprabha, businessman and football executive, born 4 April 1958; died 27 October 2018