The bank has a large number of retail branches and ATMs across Australia, and some back office operations in Bangalore, India.

The St.George Co-operative Building Society Ltd. was formed on 6 May 1937 in the Sydney suburb of Hurstville, with George Cross as the first chairman of the board.

The two Co-operatives merged in 1945, and with the post-war housing boom, the St.George and Cronulla Building Society expanded rapidly, with 38 branches established by 1955.

The then Premier of New South Wales, Neville Wran, later stood outside a branch and said he could personally guarantee the society's financial security.

[4][5] In the 1990s, the headquarters moved to Montgomery Street, Kogarah, and in 1992, the society gained its banking licence, demutualised, and became a public company.

[7] In 1991 St.George made its first interstate acquisition by buying the Victorian Savings and Loan Society, which had branches in a number of regional cities and towns.

Previously, Westpac Banking Corporation had purchased the old Bank of Melbourne business in 1997 (a separate and independently operating building society located in Melbourne), and after some preliminary steps, subsequently closed its doors in 2002 and merged the remaining operations under the Westpac banner.

In late 2010, Greg Bartlett announced that he would step down as chief executive officer in December after a long and successful tenure with the company.

St.George typically promotes itself as more friendly and customer-service-oriented than the "big four" banks operating nationally in Australia,[citation needed] although it is now a part of the Westpac Group.

[13] Despite its roots as a building society specialising in home and consumer lending, today the bank provides funding to a variety of specialist industries and market segments including commercial property construction and development, invoice discounting, interest rate hedging, foreign exchange, trade finance and automotive finance (formerly the Barclay Bank Business).

This is in addition to the approximately 70 information technology jobs that had been moved to the Indian firms Tata Consultancy Services and Hindustan Computers Limited.

St.George bank has begun to reverse the trend to offshore processing, bringing card operations back to Australia.