In the 1950s, Gandel took control of his parents' women's clothing business (then named Sussan) in the 1950s and with his brother-in-law Marc Besen grew it into a chain of over 200 stores. In 1983, he bought the Chadstone Shopping Centre, selling Sussan to his brother-in-law in 1985 to concentrate on real estate. He subsequently built his own fortune in shopping centres.
In July 1983, the Myer Emporium sold the Chadstone Shopping Centre to the Gandel Group for A$37 million, which has since managed and developed the complex into Australia's biggest shopping mall which is now valued at over A$3 billion. In July 1983, the Myer Emporium also sold the Northland Shopping Centre to the Gandel Group. Gandel's major assets are 50 per cent shares in Chadstone, and a 17 per cent stake in the listed Vicinity Centres that owns the other half. Gandel also owns significant stakes in listed property companies, besides the stake in Vicinity, worth about A$800 million, and a 15 per cent stake in Sydney-based property group, Charter Hall, in which he invested A$151 million. In more recent years, he has started to wind down his full on involvement with the company and has since hired Peter Bird as the chief financial officer