"Today is a new day, and hopefully it is full of bright sunshine and hope," 42-year-old Pita Limjaroenrat told a room packed with reporters and flashing cameras, hours after it had become clear that he could well be Thailand's next prime minister.

Mr Pita's party, Move Forward, which in Thai evokes leaps of change, has swept to a surprising and stunning victory. Voters rejected nearly a decade of army-backed rule, handing more seats and votes to Move Forward than any other party. That is is no mean achievement in a country that has experienced at least a dozen successful coups.

"The sentiment of the era has changed. And it was the right timing," Mr Pita said, speaking at the party's headquarters in Bangkok, where it had won 32 of the city's 33 seats.

The business of forming a government is still weeks away. It can also get messy, given that Thailand's military still has the power to play kingmaker. But the win has put the spotlight on Mr Pita and his party, who have built a strong following among young voters disillusioned by years of military rule and hungry for change.

Mr Pita started his political career when he was elected to parliament in 2019 as a member of the Future Forward Party. Founded by Thanathorn Juangroongruangkit, a billionaire and staunch critic of the army, the party performed well in the 2019 election, shaking up Thai politics with its demand for change.

But Future Forward was forced to disband the following year after contentious allegations. And Mr Thanathorn was disqualified as an MP. Move Forward was formed soon after as its successor and named Mr Pita its new leader.

Thousands of young people took to the streets in Thailand that year after the ban, demanding amendments to the constitution, a new election and an end to the harassment of rights activists and state critics.

That desire for change and many of those very issues drove Move Forward's appeal in this election, with some of the protest leaders from 2020 running as candidates.

Mr Pita - once called a "rising star" of the Thai parliament because of the critical speeches he made as an opposition MP - also gained popularity with his party's bold promises to break the military's political influence and reform laws relating to the monarchy.

He wants to rewrite the constitution and has pledged to bring Thailand out of what he calls a "lost decade" under a military regime.

In a campaign interview with Bloomberg in April, Mr Pita said his priorities for Thailand were to "demilitarise, demonopolise and decentralise".

Move Forward will also continue to push for an end to Thailand's lèse-majesté laws.

"We will pass that in this parliament. And we will use the parliament to make sure that it is a comprehensive discussion with maturity, with transparency, in how we should move forward in the relationship between the monarchy and the masses," he said on Monday.

Mr Pita was born to a wealthy Thai family involved in politics. His father was an adviser in the agriculture ministry and his uncle was an aide of former ousted PM Thaksin Shinawatra.

He was sent to school in New Zealand, which is when he developed an interest in politics.

"I got shipped to the middle of nowhere in New Zealand and there were three [TV] channels back then. Either you watch Australian soap operas, or you watch the debates in parliament," he told the Thai YouTube programme Aim Hour earlier this year in February.

Mr Pita graduated with a bachelor's degree in finance in Bangkok's Thammasat University, a master's in public policy from Harvard University and an MBA from the Massachusetts Institute of Technology.

He has described himself as "an American product of public policy schools".

He started his career in business, first taking over the running of his late father's rice bran oil company and later as an executive director of ride-hailing company Grab Thailand.He was married to Chutima Teenpanart, a Thai actress-model, but the couple divorced in 2019. He is now a single dad of seven-year-old Pipim, whom he has brought to Move Forward's rallies.

Despite Move Forward's success at the polls on Sunday, it is not a given that he will become prime minister - this will be decided by the military-appointed Senate and the Lower House.

Asked on Monday about the uncertainty that the ruling establishment might rig the polls, Mr Pita said: "I'm not worried, but I'm not careless.

"With the consensus that came out of the election, it will be quite a hefty price to pay for someone who is thinking of abolishing the election results... The people of Thailand will not allow that to happen."