In a new role for the retailer, Bell-Brown will have responsibility for all site acquisitions, town planning and property communications. He joins Sainsbury's on 21 November and will report to property director Neil Sachdev.
Prior to DSG, he was head of property at Halfords and has also worked for Boots.
"Sainsbury's ambitious expansion plans have been well publicised so it is an exciting time to join," Bell-Brown said. "Sainsbury's property team has a reputation for not only meeting challenging targets, but for taking an approach that focuses on the communities served by its stores."
Sainsbury's has pledged to grow its gross space by 7% to 8% in 2011/12 and then to add around 1.25 million sq ft of new space per year thereafter.