Dick Smith

He's been called a hypocrite, a pest, an egomaniac and a shameless self-promoter. But also gutsy, generous and passionate about making Australia a better place. Dick Smith never sits still and never shuts up. He's the wildcard in our pack of megaphones.

Unlike the other contenders, Smith doesn't have a regular column or radio show to air his views. This means he sometimes struggles to influence the national debate.

"It's so frustraaating," he tells The Power Index in his scratchy singsong voice. "I have so little influence in what I'm trying to do."

He says his latest book, Dick Smith's Population Crisis, has been "the greatest flop in publishing history". And no suitable young Australian has yet emerged to claim his offer of $1 million for coming up with a vision to wean Australia off its "growth addiction".

But don't let the self-depreciating Sydneysider – "I'm just a car radio installer!" – fool you. He's influential and, deep down, he knows it. That's why he spends so much time and money fighting for the causes in which he believes.

Like halting population growth, one of current causes célèbres. Smith first became interested in the topic in September 2009 when his daughter, Jenny, asked why people worried about climate change were not mentioning the "elephant in the room" – population. He decided to investigate.

"When I started on the campaign and spoke to politicians, they said, 'Dick, you can't talk about it because you'll be either declared a racist or the Murdoch press will attack you.' I didn't care what I was called; I said that was a good enough reason to talk about it."

He was soon flying around the country calling for a two-child policy, the migration intake to be slashed 70,000 a year and for Australians to end their obsession with consumption.

Pro-growth advocates accused him of hypocrisy – Smith has a holiday house, a farm, a large house with a swimming pool, two cars, a steam train, a private jet and a helicopter – and of over-simplifying a complex issue.

But his "little Australia" campaign proved a hit with the public and soon became a key election issue. Politicians and talkback radio hosts lined up to talk to him and his ABC documentary, Dick Smith's Population Puzzle, was a ratings triumph – especially in Sydney where 378,000 tuned in. Julia Gillard and Tony Abbott went to the polls repudiating Kevin Rudd's vision of a "big Australia" of 36 million.

Today, Australia's population continues to grow – albeit at a slower rate and we have a population minister for the first time.

"The influence I had was to allow people to talk about it," Smith says. "The lid is off and anyone can talk about it now – and everyone is.

"Even the [pro] growth people say you have to stop growth one day. All they're saying is, 'let's put it off for someone to worry about it'. They just mean growth until they're dead."

"Dick Smith has a genius for creating headlines," Smith's friend Phillip Adams tells The Power Index. "He's got this boyish innocence. He looks like a little Harry Potter creature. He has a radiance of confidence. He's not pompous, he's not malicious. He can be terribly irritating."

Smith claims that he's got no close friends, but seems to be mates with everyone –John Howard, John Singleton, Alan Jones, Bob Brown and Tony Abbott to name a few.

The 67-year-old has the energy levels of a kid on red cordial and bucket loads of charisma. He's also got something less obvious, but just as important: credibility. Year after year, he finishes near the top of Reader's Digest's "Most trusted Australians" list – a remarkable result given he's been so outspoken for so long on many controversial issues.

When Smith was anointed Australian of the Year in 1986, he successfully used his position to campaign against cigarette advertising aimed at young people. He bought full-page ads naming members of tobacco company boards and congratulating them on becoming the leading brand smoked by teenagers.

During the Howard years, he took up the plight of the stateless asylum seeker Peter Qasim who had been languishing in detention for almost seven years. Smith – a self-described supporter of tough border protection policies – visited Qasim at Baxter detention centre, lobbied government ministers and offered to fly to war-torn Kashmir to investigate Qasim's credentials. The media belatedly picked up on the story and within months Qasim had been released.

Emboldened, Smith then took on an ever harder case: winning a fair trial for David Hicks. At the time, few other individuals were willing to stick out their necks to defend the rights of an accused terrorist. Smith received hate mail accusing him of being a traitor and a terrorist supporter – but he kept on campaigning, both in public and behind the scenes (including to his friend John Howard). He also donated $50,000 to pay for Hicks' legal costs and plane tickets for his family to visit him at Guantanamo Bay. It took two years, but Hicks' treatment eventually became a hot-button issue with most Australians coming round to his point of view.

Smith has also been a long-time advocate for Australian-made products, aviation reform, environmental conservation and, more recently, action on climate change. He's also taken on the Murdoch-owned media (the "evil empire" in his words) and anti-vaccination zealots. Lefties love him, but he describes himself as a "conservative voter" (he ticked the Liberal box in both houses at the last federal election).

His latest crusade is perhaps his most challenging yet: trying to convince wealthy Australians to donate more to charity.

On this issue, Smith certainly can't be accused of being a hypocrite: the man who made millions selling electronics gives away 20% of his income each year to charity.

"Because I'm not religious I have to rely on karma and karma says that if you do something good, something good will happen to you. My giving is totally selfish; it makes me feel good."

As does having a say on the future he wants for his country. And on that note, don't expect Australia's most-loved media tart to disappear from sight any time soon.

"The greatest compliment is that I get stopped often in the street and people shake my hand and say, 'keep saying it how it is'. Never did I know when I was a kid, and I was dyslexic and hopeless, and all my friends were going off to university and I was working in a factory doing process work ... that I would ever be able to say it how it is.

"I can say it how it is and I'm going to."