Chuwit Kamolvisit's Love Thailand party won four seats after he reinvented himself as an anti-corruption campaigner

He was the pithiest and most peculiar candidate in Thailand's general election – and now he is its most surprising winner.

No one was more startled than Chuwit Kamolvisit, the former brothel tycoon who reinvented himself as an anti-corruption campaigner, to learn that his Love Thailand party had won four seats.

He had hoped for two at best, but won support as the anti-politics candidate in a vicious contest between the incumbent Democrats and the Puea Thai opposition fronted by Yingluck Shinawatra.

Startling quotes and attention-grabbing posters added to his appeal. "Politicians are like diapers: you have to change them often or they are too dirty," said the moustachioed party boss, explaining why he was cuddling a baby in one advert.

He shared another advert with his white bull terrier, and screwed up his face in rage on a third. "The dog is a symbol of loyalty – every country needs loyalty from politicians, but we never get it. We only get it from dogs," he said.

"And my angry face – people say, Mr Chuwit, why is your face so angry? I say, politicians become actors, and my campaign is about opposition."

He said his manifesto was entirely serious, however, adding that people are sick of the Democrats, Puea Thai and of crooked politics in general. He vowed from the start that if elected he would serve in opposition as a watchdog.

Chuwit became an unlikely hero after he lifted the lid on widespread corruption by exposing the massive bribes he had paid to police to keep his brothels running.

"We all make mistakes, but I accept I did massage parlours. None of the politicians accept they made mistakes," he added.

"Politics is no different from my former business – except that it is more dirty."

He has already begun attacking Yingluck's coalition deal with four minor parties. "She says she has a vision for 2020, so how come she uses these dinosaurs?" he asked.

"This is not a vision for nine years ahead. It's back to the past, not back to the future. She should see the movie. They are helping themselves to a buffet of food. They are trading for the ministries and I will be monitoring them. I'll be telling them: no [jobs for] husbands or wives or sons."

Professor Thitinan Pongsudhirak, a political expert at Chulalongkorn University, said Chuwit represented a protest vote. "He is not a spoiler; he's a maverick ... He doesn't offer any policy platform except scrutiny."

He added: "People are disillusioned with the Democrats but find Puea Thai unpalatable because of the Thaksin connection. He offers a third way, but the scale is not big enough to make a difference."

Thitinan said the campaigner might have won even more seats had he put up candidates in constituencies, as well as on the party list.

Chuwit said he spent 10m baht (£204,000) on the campaign and compared his pursuit of elected office to an addiction. He won a national assembly seat in 2005, but was disqualified on a technicality, and ran for Bangkok governor twice. Assaulting a news anchor who interviewed him may not have helped his last campaign.