Australia’s most powerful businesswoman, banker Gail Kelly, adopted a valuable philosophy early on in her career: even when she didn’t think she was ready for whatever job she was offered, she would accept the challenge and ‘have a go’, in the parlance of her home country.

This principle has stood her in good stead. In a 35-year career in banking – firstly in South Africa, and subsequently Australia – Kelly has progressed from teller to chief executive, smashing through the glass ceiling along the way.

Appointed chief executive of Australian retail bank St George in 1980, which under her stewardship became the first lender in Australia (and the second in the world) to launch internet banking, in 2008 she was given the top job at parent company Westpac, Australia’s second-biggest bank. Taking advantage of the country’s booming mortgage market, she has presided over steadily mounting returns. Amply rewarded for her work, Kelly earned $9.5m in 2014 alone.

A former Latin teacher and mother of four, including triplets, Kelly has adopted as her guiding light the conclusion of management guru Jim Collins, who found it was vital that a company “has the right people on the bus and the wrong people off it”. If her employees don’t fit in, they are helped into other roles – or outside the bank altogether.

And cutting through the management jargon that often typifies senior bankers, she has reduced Westpac’s philosophy to the simplest possible message. In fact, it’s just one word: ‘helping’. Helping customers, that is.

Unusually, at least when compared to her male peers in the industry, Kelly often eschews ‘banker talk’ in favour of what some might see as touchy-feely language, but which others see as philosophical and heart-felt. In any case, it makes her an approachable CEO.

In a candid address in August, she explained that the mainspring for her improbably spectacular career was a particular moment of clarity she had experienced. As a young teacher, she suddenly realised in a dark moment that she had lost the optimism and cheerfulness that her parents had taught her. “I recognised that I needed to make a change either in my attitude or in what I was doing”, she said. So she gave up teaching and became a teller in a South African bank.

Now 58, Kelly manages to combine a swathe of extracurricular activities with her day job. As well as being the chairwoman of the Australian Bankers’ Association, she serves as Australia’s official ambassador for women’s empowerment, is a member of the G30, and is vice president of the International Monetary Conference. That’s quite a CV, given the demands of her position.

At Westpac, Kelly relentlessly pushes change. Her current pet project is the ‘service revolution’ – a bank-wide campaign designed to challenge threats to traditional banking, such as the likes of PayPal and Google.

Indeed, one of Kelly’s key executives is known as a ‘core transformation group general manager’. This isn’t merely lip service – in late 2014 she formally opened The Hive, an AUD 5m innovation hub built from scratch in just three months. “Innovation is the idea of being first, of being front-footed… it’s very much part of our DNA”, she said.

In short – have a go.