Therese Rein (pictured) has never loved the spotlight.

As one of Australia’s most successful business women, it’d be hers if she wanted it, regardless of the fact that she’s the wife of a former prime minister. But while she’ll speak at universities and has from time to time told her story on her own terms, she rarely accepts the media requests she must be inundated with every time she does something significant.

Yesterday was no exception. Throughout reams of coverage on her sale of the business she founded and mostly owns to a United States employment firm, Providence, no one snared an interview. The part of the statement quoting her was brief:

“Providence will provide the financial underpinning and complementary knowhow that will enable us to fully achieve our goals. We expect the scale and collective capabilities of the combined businesses will enhance our service delivery and open doors for winning new business.”

A statement put out by Ingeus rehashed the same dry quote. But if anything is assured through her sale of Ingeus to Providence, it’s that Rein will never be free of the limelight again. If Rein, who’ll stay as managing director of Ingeus for at least five years, meets certain performance targets, she could personally earn up to $151 million in cash and shares. That could almost double her wealth in the next five years, ensuring that if nothing calamitous happens, she’ll be on every Rich List for the rest of her life.

Rein graduated from Australian National University in 1981, and six years later started working part-time as a rehabilitation councillor. It was a passion sparked by her personal experience with her father — he lost the use of his legs after serving in the Air Force during World War II. Doctors didn’t expect he’d work again but he ended up working until he was 65 as an aeronautical engineer.

Rein said in a 2003 business book, Marketing without Money:

“I don’t like people being thrown on the scrap heap. Enabling people to reconnect with their communities, to reconnect with independence, to reconnect with their potential — I think that matters.”

Only three years after she began work, she founded her own company with now deceased business partner Frances Jane Edwards. Work Directions Australia, as Ingeus was then called, benefited from the outsourcing of many government functions that began in the 1980s. In 1993, the company won its first contract from the Hawke government, and continued to execute major contracts for the Howard government’s Job Network agency.

Rein wasn’t content to grow a solely Australian company. The business has been in the United Kingdom since 2002. It went into France in 2005 and Germany in 2006.

Edwards died in 2006. When Rein’s husband stood poised to become prime minister in 2007, the business sold it’s Australian arm (Rein told The Courier-Mail at the time it wouldn’t be sensible “for my company to receive even one dollar of a federal government budget if Kevin was elected prime minister”). This wasn’t much of a slow-down — the company’s expansion merely increased as a result of it. It’s expanded into Asia and the Middle East; it’s now got a flag in 10 nations. It’s also back in Australia — the company bought Brisbane-based organisational development company Assure Programs in 2011.

But the UK business is the big one — a joint venture with Deloitte, it’s responsible for 70% of the company’s total revenue. Ingeus is the biggest player contracted by David Cameron’s government to find work for the long-term unemployed. The scheme has come under fire recently, with rival companies being accused of fudging their success rates by getting the unemployed to work in their own offices. There have been few concrete allegations against Ingeus, but the mud from the scandal has nonetheless soured the company’s British success.

Why has Rein sold the business now? Ingeus teamed up with Deloitte for its resources in rolling out its business across the UK. But Deloitte has been looking to sell out of the British operation since last year. Yesterday’s sale means they have finally done so. Partnering up with Providence shows Ingeus repeating the pattern – a buyer with resources can help it expand even further.

For Rein, the journey continues. Given her next payday relies on meeting certain targets, she’s no doubt pleased by the sharemarket reaction to the acquisition: Providence’s market price rose 34% yesterday.