By training job candidates before hiring them, the financial services giant has slashed turnover — and aspiring agents get the chance to test-drive a new career while still in their old jobs.

FORTUNE -- As an account executive at risk management and reinsurance firm Aon, Darryl Thompson made a time-consuming daily trek between Manhattan and his home in suburban White Plains, N.Y. "I was unhappy about not spending enough time with my eight-year-old son," Thompson says. "I wanted more control over my own schedule."

Then, in 2010, a friend who worked for Prudential told him about an unusual recruiting method the company had launched the year before. Called the CDP, for Career Development Program, it allows people to stay in their current jobs throughout six months of training -- mostly online, and at the candidates' own pace -- to earn the professional designations required to become a certified life insurance agent and financial advisor.

Thompson decided to give it a try, and ended up quitting Aon (AON) to join Prudential (PRU) full-time in April 2011. As a seasoned property-and-casualty broker with an MBA in finance, Thompson might seem to have an edge over most who take Prudential's training, but he says not. "Many of my colleagues in the program were liberal-arts types like teachers and musicians," he says. Has the career change worked out the way he hoped? "Absolutely. I work even longer hours now, but I have much more flexibility," he says. "I wish I could have done this years ago."

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Prudential launched the CDP in 2009 as a small-scale experiment, but it's worked so well that it's now the only way the company hires new financial professionals, some 3,400 of whom have done the training so far. "The way we used to hire people was much more the traditional method of interviewing them, hiring them, and then training them," says Caroline Feeney, Prudential's newly appointed president of agency distribution.

"Our managers like this approach a lot better, because it shows them clearly how committed and conscientious each candidate is before that person is hired," she adds. "As candidates go through the training, you can see very clearly who's committed and motivated, who really 'gets' the sales aspect of the business, who's enthusiastic and who isn't. It tells you volumes more than any job interview can." More