When 94-year-old billionaire Len Ainsworth started making poker machines, Australia was a very different place: Robert Menzies was prime minister, thousands lined the streets for the first visit of the young Queen Elizabeth II and Nat King Cole dominated the charts.

"I was busy making dental supplies — my father having been a dentist — and he made dental supplies and equipment as a hobby. He said I ruined his hobby by turning it into a business and actually, I did do that," Mr Ainsworth remembers.

It was the early 1950s; Len was a young man in his 20s.

"This fellow Joe Haywood — an Englishman, a very bright fellow — asked me if I'd ever thought of making a poker machine," he says.

"So I said 'what's that? I don't know about them'. So he said, 'it's got a handle, you put money in them, you spin the reels and you might even get winnings from it'."

It was the chance jackpot any poker machine player would dream of.

But Mr Ainsworth had no idea what was to come: two personal fortunes and a reputation as the icon of one of the most controversial legal industries in the world.

His rise is documented in the new ABC podcast series How Do You Sleep At Night?

Len Ainsworth says claims that pokies are designed to be addictive are "nonsense". ( ABC News: Sarah McVeigh )

Back then, the plan was simple — Len and Joe would make the machines, to get the money, to build the dentist chairs. That was the big dream.

They called their company Club Man. Poker machines weren't legal yet, but it wasn't long before an agent came knocking.

"The contract in the first place was for two machines a week, and within a week he was back saying 'could he have four a week?'" Ms Ainsworth remembers.

"Then another week went past and it was eight a week… and then it became 16 a week… and then it became 32. And each time Joe said, 'can do'."

'You're in the big league now, son'

By late 1954, Mr Ainsworth had made his first enemies.

"I had a phone call from Joe, who lived next door to the factory. And he said, 'our roof's been blown in with a gelignite bomb'," he says.

"I went out and there were fire engines in the street, ambulances in the street, police everywhere. And there was a little man from The Telegraph dodging around with a photographer on his heels and he said to me, 'who did this?' and I said, 'I've no idea'.

"He said, 'do you think you've got enemies?' I said 'you know, I'm beginning to wonder'.

"I suppose I was surprised. I'm a calm person.

"The police said to me 'buy a shotgun and put chicken wire on your windows. You're in the big league now, son'."

In 1956, the pokies became legal in the pubs and clubs of New South Wales and Ainsworth's dreams grew bigger. He had ditched the name Club Man and his new company, Aristocrat, was born.

"I went to America and my eyes nearly popped when I saw the machines in Reno," he says.

"I was transfixed. I said 'I've just seen something that will make me a million'."

Family fortunes and a new rival company

Len's rise and rise continued and as it did, his family grew. He had five boys to his first wife and another two to his second wife.

In 1994, a prostate cancer scare changed everything. His doctor told him he could be dead within the year.

"I thought the best thing to do would be to divide my estate up — which included the whole of Aristocrat at that time — and give it to my wife, my ex-wife, and my seven children," he says.

"So I divided it nine ways and gave it away."

But then after giving it all away, he got better, and his family became very wealthy.

There are around 200,000 machines — roughly one per 100 people — in Australia. ( Flickr: Carol Von Canon )

Two years after the cancer scare, Aristocrat was floated on the Australian stock market, the share price went up, and so did all his family's fortunes.

Rather than retiring, the pokies king decided to have another crack at business — he started a rival pokies company called Ainsworth, which he runs to this day.

"Manufacturing is in my bones, really. I have to make things. That's what I like doing. So I'm a relatively creative person," Mr Ainsworth says.

"I am not an artist, but I can tell whether something is right or whether it's wrong for our industry. So I've been very fortunate in that direction."

Pokies are entertainment, or 'amusement with a price'

Every year, Australians put $13 billion through the pokies. We have around 200,000 machines — roughly one machine per 100 people.

The states make significant revenue from them, despite growing warnings from public health experts about the damage these games can do.

But Mr Ainsworth describes claims that pokies are designed to addict as "total rubbish" and "nonsense".

Every year, Australians put $13 billion through the pokies. ( ABC News: Diana Hayward )

"I mean, if you like something you'll continue to do it," he says.

"It's like kissing girls. Tell me the man that stopped kissing girls because he didn't like it."

Mr Ainsworth says his job is to provide entertainment, "or, as the English would say, amusement with a price".

"We do that very successfully. We make all kinds of features to entertain people, and it's really up to them from there," he says.

"I'll feel responsible for what individuals do when General Motors feel responsible for the accidents that some nut at the wheel might have."

Mr Ainsworth says his job is to provide machines which keep his customers happy, and their job is to be responsible to their customers — the people who play machines.

"I think if you can't control yourself, whether it's gluttony or where it's playing machines or whatever, well it's time you took some lessons," he says.

You can hear more about Len Ainsworth's life and career and how he responds to judgement in the new ABC podcast How Do You Sleep At Night? You can binge all six episodes now on the new ABC Listen app or get one a week on itunes.