Seinfeld has only represented two other organisations in his career Microsoft and American Express but the Greater is said to have won Seinfeld because he liked their campaign concept.

Under the deal the American comedian and television star will appear in television, radio, print and web advertisements for the 250,000-member financial institution over the coming years.

There has been no word on how much the building society paid to secure the star except that it's somewhere "between $10.50 and $10million", the rumoured figure Seinfeld got from Microsoft.

Seinfeld was heavily involved in writing scripts for the campaign but because of his schedule the commercials were filmed just outside New York.

The small town, called Cedarhurst, was transformed to a typical Australian street with mock shopfront for the two-day shoot in May.

In the first of the series of commercials, Seinfeld sets up a stage outside a branch and entertains passers-by with his observational comedy as a segue into the benefits of banking with the Greater. The building society will launch the campaign today with the first commercial to appear on regional stations on Sunday night.

The campaign to secure Seinfeld started in January when Greater marketers pitched their idea to the star's manager of 30 years, George Shapiro.

Greater marketing head John Dwyer said they had a shortlist of possible celebrity spokesmen but Seinfeld was at the top because his clean-cut yet cheeky style matched the brand.

"Jerry's humour is all about everyday observations and at the Greater, we have historically used real customers in our marketing, all of whom make everyday observations about their relationship with the Greater," he said.

"We didn't think in our wildest dreams he would say yes."

Mr Dwyer said Mr Shapiro loved the Greater's proposal and emailed it to Seinfeld who responded a few days later to say he also loved the idea and was on board.

Seinfeld replaces former television journalist John Church as the face of the Greater.

Seinfeld is tipped to return to television later this year with a reality program about marriage.