With his floppy hair, baggy shorts and stripy T-shirt, accessorised with a yellow ribbon around each skinny wrist, the only thing distinguishing the 17-year-old from the other teenagers on Wednesday was the bank of television cameras facing him.

Joshua Wong is too young to drive or buy a drink in a bar – let alone vote – yet has become the face of the pro-democracy protests in Hong Kong and an inspiration to citizens three times his age.

The co-founder of Scholarism, the student movement which kickstarted the demonstrations, is already a veteran activist. At 15, he battled against plans to introduce “national education”, which critics attacked as pro-Beijing “brainwashing”. Scholarism’s campaign brought more than 100,000 people on to the streets in protest; the proposals were duly shelved and Wong became something of a celebrity. He is probably the first mass protest leader who has had to call a press conference to discuss his exam results (he met university entrance requirements, though he has said in the past: “Teachers have always said my only strength is talking and that I talk very fast.”)

But his 40-hour detention from Friday, along with others who stormed into the blocked-off government complex at Admiralty, kickstarted large-scale protests and catapulted him to global attention. The arrests galvanised those previously indifferent to last week’s student protests and sparked the wider civil disobedience movement that has paralysed a large part of downtown Hong Kong.

The sudden fascination with Wong’s role is not entirely to his satisfaction. “If a mass movement turns into worshipping a particular person, that’s a great problem,” he warned in 2012, after the campaign against national education. More recently, asked about his own heroes, he stressed: “You don’t need role models to be part of a social movement as long as you care about the issues.”

Joshua Wong speaks to fellow students on the street outside the Hong Kong Government Complex. Photograph: Chris McGrath/Getty Images

Since his release on Sunday – ordered by a judge who said police had held him for an unreasonably long time – he has declined to discuss what happened in detention or to be drawn into discussing his career as an activist. On Wednesday he parried such queries politely but firmly: “These personal interview questions we can ask later.”

Chinese state media have attacked Scholarism as extremists and a pro-Beijing Hong Kong-based paper claimed that “US forces” had worked to cultivate Wong as a “political superstar” – accusations Wong has dismissed.

Despite his ardour and bluntness he is not a rabble-rouser. “He’s passionate but measured; measured beyond his years,” said Michael Vidler, the human rights lawyer who acted for Wong following his detention.

“He’s so young but so wise that you can’t help but have a lot of time for him … He is every mother’s son – filial, polite, principled, hard-working.”

Vidler described Wong’s parents, Grace and Roger, as “a very quiet, middle-class, ordinary family”, rather than activists.

Wong has said: “They are not helicopter parents and do not spoil me … They have given me freedom, which has shaped Joshua Wong as he is now.”

But they have taken part in protests in the past and in a blog post a few years ago, Wong said his father had started taking him to visit the poor and suffering when he was a child: “He told me that I should care for the abandoned in the city. They had not heard of the gospel, and were living solitary and hard lives.”

The couple have described their son’s detention as political persecution, adding in their statement: “We have always brought up Joshua to be compassionate, caring, principled and loyal and we are very proud of all that he is doing to make Hong Kong a better place for his generation and our generation.”

While he has focused on the battle for democracy, Wong has also sought to bring more citizens into the fold by spreading the message that politics is about ordinary life, not a disruption to or distraction from it.

“Why does a tofu roast pork belly lunchbox cost HK$50 [£4], and $8 more for a drink? Why does the eastern rail line break down weekly, but fares never stop rising? ... Many issues are closely related to politics and I think Hong Kongers should pay more attention to politics,” he told the South China Morning Post.

Joshua Wong with activists outside the National Day flag-raising ceremony. Photograph: Eyepress/SIPA/Rex

On another occasion he compared the need for public nomination to picking lunch, saying that imposing tight controls on candidates for the role of chief executive was like offering people the chance to eat at one of two shopping centres.

“Is it a real choice? The inside is very similar: you end up eating Pepper Lunch anyway,” he said.

That such a young figure should emerge as the symbol of the protests is apt, if surprising: crowds have been overwhelmingly youthful – a reflection of the organisational work done by Scholarism and the Hong Kong Federation of Students over recent years, but also of a generational shift in identity.

“Hong Kong has a bright future because of our youth; I feel so proud of them,” said Martin Lee, the 76-year-old sometimes referred to as the region’s “father of democracy”. “It’s their Hong Kong – it’s their future.”

Wong has said that matters are already out of his hands, and those of other activists.

“I can’t predict what will be the outcome and how long we can continue with this action. Actually, this decision should be for the citizens, not Scholarism, Occupy Central with Love and Peace or others,” he said on Wednesday.

The spontaneous nature of the civil disobedience put more pressure on the government and made it harder for them to target individual leaders, he said. He has faced unwanted attention: he believes his phone is tapped and has said that on his graduation break in Taiwan he was followed by a man who said he had been “commissioned by a company to watch me”.

Such “inconveniences” have not put him off, but he acknowledges that even he gets tired of discussing political reform at times, and insists he has a life outside activism.

His greatest success as a campaigner may have been to prove that his role has its limits, because so many more people have been drawn in.

“Many citizens have said to me that ‘Hong Kong relies on you’ and some even called me a hero,” he wrote in an essay posted on his Facebook page on Wednesday.

“I feel uncomfortable and even irritated when I hear this praise. When you were suffering pepper spray and teargas but decided to stay for the protest despite the repression from the government, I was not able to do anything other than stare at a meal box and the blank walls of the detention room and feel powerless.

“The hero of the movement is every single Hong Kong citizen.”