Tommy Cheung, a round-faced 25-year-old former student activist, did not expect to emerge a winner in the electoral battle for Yuen Long district council, a heavily conservative rural corner of Hong Kong and a stronghold of clan power.

But early on Monday morning, he was pleasantly surprised to find that he had secured 3,177 votes, nearly 900 more than his opponent, the incumbent deputy chairman of the Yuen Long district council, who hails from a powerful local family.

Cheung told the Guardian that his victory was less to do with the success of his personal campaign than the fact that Hong Kong people desperately wanted to make their voices heard and their political demands satisfied.

“It has little to do with me – it is the tsunami of public opinion,” he said. “Pro-democracy candidates have won in all the districts.”

Months of pro-democracy protests, from a two million-strong peaceful march in June over a controversial extradition bill, to increasingly violent street demonstrations that culminated in a siege of a city-centre university, has turned the previously sleepy district council elections into a proxy referendum on the Hong Kong government.

There is widespread dissatisfaction on the government’s refusal to negotiate or compromise with the protesters, but instead used the police force to deal with the escalation of the increasingly radical protests.

Many seats in previous elections were uncontested and for years were packed by well-funded pro-Beijing candidates who promised residents better local services and benefits.

Cheung, a non-local, does not have the wealth of resources like the pro-Beijing or pro-government candidates, but his political campaign promised to investigate an incident on 21 July when dozens of white-clad thugs carried out an indiscriminate attack on commuters and protesters at the Yuen Long metro station.

Only six have been charged over the incident that is widely seen as the collusion between thugs and the police to punish protesters returning to Yuen Long from a mass protest in town late that night.

“The July 21 incident has antagonised a lot of local residents and they voted to voice their dissatisfaction,” Cheung said.

His campaign also pushed for “genuine universal suffrage”, as he and other candidates want the government to launch democratic reforms – a demand that failed in the 2014 Umbrella movement.

Cheung, a student at the time, was found guilty of charges including “inciting others to cause public nuisance” and sentenced to a community service order of 200 hours this year. Other more high profile activists, such as professors Chan Kin-Man and Benny Tai, were given 16 months in jail.

On Sunday, a number of local Yuen Long residents also told the Guardian that they were fed up with the ongoing violent conflicts, in which radical protesters threw petrol bombs and bricks at police and block roads in an attempt into pressuring the government to give in to their political demands. Many said they came out to vote to support the government to act tougher on the young protesters and criticised the pro-democracy camp for endorsing the movement that has turned increasingly violent.

“I am an advocate of the peaceful and rational approach,” said Cheung. “I think people look at your political ideals.”

Asked whether he might now be afraid of retribution from the conservative local camps and worry whether he might even be physically attacked as political divides continue to deepen, Cheung said he would not be deterred.

“I am not worried,” he said. “If that sort of stuff happens again, the tide of public opinion will be even firmer.”